Heat-bonding apparatus and method of manufacturing heat-bonded products

ABSTRACT

A heat-bonding apparatus and method of manufacturing a heat-bonded product not allowing the temperature of the object to be heat-bonded to overshoot greatly from a specified target temperature suitable for heat-bonding, and setting the temperature of the object to the target temperature in a shorter time and with higher efficiency and accuracy than the conventional when heat-bonding in vacuum. A heat-bonding apparatus having a vacuum chamber for housing an object to be heat-bonded and a buffer part, a heater for applying heat to the buffer part in contact with the object in the chamber, a cooler for discharging heat of the buffer part, a sensor for detecting temperature of the object heated through the buffer part and a controller for controlling the temperature of the object to be the target temperature by adjusting heat discharge from the buffer part with the cooler based on the detected temperature of the object.

TECHNICAL FIELD

The present invention relates to heat-bonding apparatus and method ofmanufacturing heat-bonded products and, more particularly, toheat-bonding apparatus and method of manufacturing heat-bonded productsfor heating and cooling to bond a workpiece, which is a heat-bondedobject including and configured of electronic components, substrates andbonding materials.

BACKGROUND ART

A soldering apparatus is known in the art as the heat-bonding apparatus,having a heating means, in which a heating plate is provided in anopenable chamber filled with reducing carboxylic acid vapor (see PatentDocument 1, for example). Part of the heating plate on which a substrateis placed is flattened, and a temperature sensor is provided in theheating plate for sensing the temperature of the heating plate. Theheating means is configured to control the temperature of the heatingplate according to the sensed temperature of the heating plate.

PRIOR ART DOCUMENT Patent Document

[PTL 1] Japanese Laidopen Patent Application No. H11-233934 (forexample, refer to Claims 1 and 7)

DISCLOSURE OF INVENTION Problem to be Solved by the Invention

In a conventional heat-bonding apparatus, however, a workpiece placed onthe heating plate can be overheated when it is heat-bonded, for example,soldered within a vacuum chamber. The workpiece includes heat-sensitiveelements such as a semiconductor device and an electronic component asthe heat-bonded objects. Due to overheat at a temperature higher than aspecified target temperature for appropriate heat-bonding of the object,the workpiece is sometimes damaged by heat. To prevent such a thermalfracture of the workpiece, the conventional heat-bonding apparatus needsto apply heat gradually to the workpiece for long duration duringheat-bonding in a vacuum atmosphere. Thus, cycle time required for theheat-bonding of the workpiece has been extended.

The object of the present invention made in view of the problemsdescribed above is to provide an excellent heat-bonding apparatus andmethod of manufacturing a heat-bonded product that do not allow thetemperature of the object to be heat-bonded to overshoot greatly fromthe specified target temperature suitable for heat-bonding, and can setthe temperature of the object to the specified target temperature in ashorter time than the conventional apparatus and method whenheat-bonding is performed in a vacuum.

Means for Solving the Problem

In order to solve the problem described above, a heat-bonding apparatusaccording to Aspect 1 of the present invention is a heat-bondingapparatus 100 shown in FIG. 1, for example, which comprises: aheat-bonding apparatus comprising: a vacuum chamber 10 for housing anobject 1 to be heat-bonded and a buffer part 5; a heater 20 for applyingheat to the buffer part 5 placed into contact with the object 1 housedin the vacuum chamber 10; a cooler 30 for discharging heat of the bufferpart 5 heated by the heater 20; an object temperature sensor 40 fordetecting a temperature of the object 1 heated through the buffer part5; and a controller 50 for controlling the temperature Tp of the object1 to be a specified target temperature Tt (see FIG. 4A) suitable forheat-bonding by adjusting heat discharge from the buffer part 5 with thecooler 30 in accordance with the detected temperature Tp (see FIG. 4A)of the object 1.

In the configuration as described above, heating of the object with theheater which has a tendency to overshoot in a vacuum can be performed bytransferring heat to the object from the buffer part where its heataccumulation is adjusted. Thus, the object can be prevented from beingoverheated and damaged by heat through direct heating of the object bythe heater in a vacuum where thermal diffusion to ambient air cannot beexpected. The temperature of the object can be controlled through theadjustment in which heat of the buffer part directly heated by theheater is discharged with the cooler. The term “to discharge heat” ofthe buffer part refers to a concept including to draw heat from thebuffer part and to cool the buffer part with lowering in temperature ofthe buffer part regardless of maintaining or changes of the temperatureof the buffer part.

Thermal diffusion to ambient air does not occur during heating in avacuum. Thus, part of heat applied to the buffer part directly heated bythe heater is accumulated in the buffer part, and rest of the heat istransferred to the object and accumulated in the object. At this time,the temperature of the object can be raised faster than the conventionalapparatus by setting the temperature of the buffer part in contact withthe object to a higher temperature independent of the temperature of theobject. The temperature of the object can be controlled to be thespecified target temperature through the adjustment of the temperatureof the buffer part with the cooler. When the temperature of the objectis to be raised, the temperature of the buffer part is raised throughincrease in heat accumulation of the buffer part, and thus thetemperature of the object can be raised faster than the conventionalapparatus. When the temperature of the object approaches the specifiedcontrol target temperature, heat of the buffer part can be dischargedthrough contact of the cooler with the buffer part, and thus thetemperature of the object can be controlled to be the specified targettemperature without overshooting.

In the heat transfer from the buffer part to the object in a vacuum, theheat transfer (rate of heat transfer, heat transfer coefficient)unpredictably varies due to the vacuum interposing between the bufferpart to the object. In this case, the detection of the temperature ofthe object and adjustment of heat discharge from the buffer part to makethe temperature of the object be the specified target temperature canreflect fluctuations (changes) in heat transfer to temperature controlof the object, and thus the temperature of the object can accurately becontrolled. Since the accurate control can be performed as describedabove, heat-bonding of the object can be performed with a temperaturerise rate larger than that of the conventional apparatus in which theupper limit on the temperature rise rate (Temperature (C)/Time (sec.))of the object is set due to an error resulting from the control of theconventional apparatus. Unlike the conventional apparatus, the heatingtemperature of the buffer part is not limited to the control targettemperature of the object or lower due to the temperature control of theobject, and the heating temperature of the buffer part can be determinedas the heating temperature that exceeds the control target temperatureof the object independently of the heating temperature of the object.Therefore, the temperature of the object to be heat-bonded does notovershoot greatly from the specified target temperature suitable forheat-bonding, and the temperature of the object can reach the specifiedtarget temperature in a shorter time than the conventional apparatuswhen heat-bonding is performed in a vacuum. Since the object is heatedthrough the buffer part, temperature can be equalized at the buffer partfor heating the object. Unequal heating of the object can be preventedaccordingly. Therefore, good heat-bonding can be conducted, andhigh-quality heat-bonded products can be manufactured.

A heat-bonding apparatus 100 according to Aspect 2 of the presentinvention is the heat-bonding apparatus according to Aspect 1, as shownin FIG. 1A and FIG. 1B, for example, wherein the heater 2 is provided asa thermal radiation heater 20 a for heating the buffer part 5 throughthermal radiation; the cooler 30 includes a cooling block 30 a and adrive unit 30 b for relatively driving the cooling block 30 b toapproach and move away from the buffer 5; and the controller 50 isconfigured to control the temperature of the object by adjustingapproach and separation of the cooling block 30 a.

In the configuration as described above, thermal radiation heater canwell apply heat to the buffer part even in a vacuum without beingblocked by the vacuum interposing between the heater and the bufferpart. The controller can efficiently control the heat discharge from thebuffer part by adjusting mutual spacing (contact or non-contact) betweenbuffer part and the cooling block in accordance with the detectedtemperature of the object. Therefore, the heat-bonding can be conductedin a shorter time than the conventional apparatus.

A heat-bonding apparatus 200 according to Aspect 3 of the presentinvention is the heat-bonding apparatus according to Aspect 1, as shownin FIG. 6, for example, wherein the buffer part is provided as a placingtable 5 b for placing the object 1, and the heater 20 b and the cooler30 c are provided inside the placing table 5 b,

In the configuration as described above, the heater and the coolerprovided inside the placing table can apply heat and cool the object tobe heat-bonded placed on the placing table through the placing table asthe buffer part. Therefore, a good heat-bonding apparatus can beprovided which does not allow the temperature of the object to beheat-bonded to overshoot greatly from the specified target temperaturesuitable for heat-bonding, and can set the temperature of the object tothe specified target temperature in a shorter time than the conventionalapparatus when heat-bonding is performed in a vacuum.

A heat-bonding apparatus 100 according to Aspect 4 of the presentinvention is the heat-bonding apparatus according to according to anyone of Aspects 1 through 3, as shown in FIG. 1A and FIG. 1B, forexample, further comprising: a buffer temperature sensor 60 fordetecting a temperature Tb (see FIG. 4A) of the buffer part 5; and avacuum breaker 70 for breaking a vacuum in the vacuum chamber 10,wherein the controller 50 is configured to break the vacuum in thevacuum chamber 10 by operating the vacuum breaker 70 when a temperaturedifference between a first detected temperature Tp (see FIG. 4A) of theobject temperature sensor 40 and a second detected temperature Tb of thebuffer temperature sensor 60 falls within a range of specifiedtemperature differences To (see FIG. 4A).

The configuration as described above can control to break the vacuum inthe vacuum chamber when a temperature difference between the temperatureof the object to be heat-bonded and the temperature of the buffer partfalls within a range of specified temperature difference. When thevacuum in the vacuum chamber is broken, heat transfer through atmospherebetween the object to be heat-bonded and the buffer part is restored.Since the vacuum is broken when the temperature difference between theobject and the buffer part falls within a range of specified temperaturedifference, the object can be protected from abrupt heat transfer fromthe hot buffer part to the object and thermal destruction. In addition,the vacuum in the vacuum chamber can be broken at the earliest possibletime in a range in which the object to be heat-bonded is not damaged byheat. The heat transfer (thermal diffusion) from the object to beheat-bonded and the buffer part to atmosphere (convection) canaccordingly be restored at the earliest possible time, and the objectcan be cooled efficiently. Therefore, overheating of the object can beprevented, and the cycle time for heat-bonding can be further shortenedas compared to the conventional apparatus.

A heat-bonding apparatus 100 according to Aspect 5 of the presentinvention is the heat-bonding apparatus according to Aspect 4, as shownin FIG. 1A and FIG. 1B, for example, wherein the controller 50 isconfigured to lower the temperature of the object 1 below a meltingpoint Tm (see FIG. 4A) of a bonding material after breaking the vacuum B(see FIG. 4A) in the vacuum chamber 10.

In the configuration as described above, the temperature of the bondingmaterial can be controlled to be below the melting point after thevacuum in the vacuum chamber is broken. In other words, the controllerperforms the vacuum break when the temperature of the object is higherthan the melting point of the bonding material. At this time, voids inan expanding state which are expanded by the residual pressure thereinin a vacuum can be compressed to a shrinking state in which the voidsare compressed again under pressure in which the vacuum break isperformed, in the joint part in a molten state which is heated to thetemperature above the melting point. After the voids in the joint partare compressed to the compressed state, the temperature of the bondingmaterial can be lowered to the solidification temperature below themelting point, and thus the bonding material can be solidified.Therefore, the influence of the voids in the joint part can be limited,and more reliable heat-bonding can be performed.

A heat-bonding apparatus 100 according to Aspect 6 of the presentinvention is the heat-bonding apparatus according to Aspect 4 or 5, asshown in FIG. 1A and FIG. 1B, for example, further comprising: a vacuumpump 80 for discharging air inside the vacuum chamber 10, wherein thecontroller 50 is configured to control the temperature of the object 1to be the specified target temperature Tt (see FIG. 4A) by adjustingheat transfer from the buffer part 5 to the object 1 through adjustingair discharge with the vacuum pump 80 and vacuum break with the vacuumbreaker 70 in combination.

In the configuration as described above, the rate of the heat transfer(heat transfer coefficient) from the buffer part to the object can beadjusted through the adjustment of the degree of vacuum (vacuumpressure) in the vacuum chamber, and thus the temperature of the objectcan be controlled to be the specified target temperature. In this case,the temperature of the object can efficiently be controlled in a freemanner, because the object to be heat-bonded can be controlled usingmultiple adjusting means.

A method of manufacturing a heat-bonded product according to Aspect 7 ofthe present invention is a method of manufacturing a heat-bondedproduct, as shown in FIG. 7 (appropriately see FIG. 1A and FIG. 1B) forexample, comprising the steps of: providing M1 the heat-bondingapparatus 100 according to any one of Aspects 1 through 6, placing toload the object 1 to be heat-bonded in contact with the buffer part 5into the heat-bonding apparatus 100; and heat-bonding M2 the object 1using the heat-bonding apparatus 100.

In the configuration as described above, a heat-bonded product can bemanufactured with high productivity because the temperature of theobject to be heat-bonded is not allowed to overshoot greatly from thespecified target temperature suitable for heat-bonding, and thetemperature of the object can be set to the specified target temperaturein a shorter time than the conventional method when heat-bonding isperformed in a vacuum.

A method of manufacturing a heat-bonded product according to Aspect 8 ofthe present invention is a method of manufacturing a heat-bondedproduct, as shown in FIG. 7 (appropriately see FIG. 1A, FIG. 1B, FIG. 4Aand FIG. 4B) for example, comprising the steps of: placing M1 a anobject 1 to be heat-bonded and a buffer part 5 under vacuum, the object1 being arranged into contact with the buffer part 5; heating M2 a thebuffer part 5 under vacuum; discharging M2 b heat of the heated bufferpart 5; detecting M2 c a temperature Tp of the object 1 heated throughthe buffer part 5; and controlling M2 d the temperature Tp of the object1 to be a specified target temperature Tt suitable for heat-bonding byadjusting heat discharge in the step M2 b of heat discharging inaccordance with the detected temperature Tp of the object 1.

In the configuration as described above, a heat-bonded product can bemanufactured with high productivity because the temperature of theobject to be heat-bonded is not allowed to overshoot greatly from thespecified target temperature suitable for heat-bonding, and thetemperature of the object can be set to the specified target temperaturein a shorter time than the conventional method when heat-bonding isperformed in a vacuum.

Effect of the Invention

According to the heat-bonding apparatus and method of manufacturing aheat-bonded product of the present invention, an excellent heat-bondingapparatus and method of manufacturing a heat-bonded product can beprovided that do not allow the temperature of the object to beheat-bonded to overshoot greatly from the specified target temperaturesuitable for heat-bonding, and can set the temperature of the object tothe specified target temperature in a shorter time than the conventionalapparatus and method when heat-bonding is performed in a vacuum.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A is a front cross-sectional view showing an example of asoldering apparatus as the heat-bonding apparatus according to a firstembodiment of the present invention, which shows a state where thecooling block is spaced apart from the buffer part and the buffer partis heated with thermal radiation heater.

FIG. 1B is a front cross-sectional view showing the first embodiment ofthe present invention, which shows a state where the cooling block isbrought into contact with the buffer part and the heat of the bufferpart is discharged with the cooling block.

FIG. 2 is a partially cross-sectional side view showing an example ofthe soldering apparatus according to the first embodiment of the presentinvention. It is a partially cross-sectional view, a side view of thesoldering apparatus according to the first embodiment, showing aninternal configuration by cutting a part of the partition wall of thevacuum chamber.

FIG. 3A is a block diagram showing the configuration of the controllerincluded in the soldering apparatus according to the first embodiment ofthe present invention, which shows functional parts included in thecontroller.

FIG. 3B is a block diagram showing the details of the functional partsincluded in the control part of the controller.

FIG. 4A is a drawing of a graph showing an example of the temperaturecontrol in the soldering apparatus according to the first embodiment ofthe present invention, and shows an example of the temperature controlin the case where the buffer part is heated to the first heating targettemperature slightly lower than the melting temperature of the solderand then the heat transfer waiting time is set for the temperatureequalization.

FIG. 4B is a drawing of a graph showing another example of thetemperature control of the first embodiment in the case where the heattransfer waiting time is not set.

FIG. 5A is a front cross-sectional view showing an example of asoldering apparatus as the heat-bonding apparatus according to a secondembodiment of the present invention, which shows a state where thecooling block is spaced apart from the buffer part and the buffer partis heated with thermal radiation heater.

FIG. 5B is a front cross-sectional view showing the second embodiment ofthe present invention, which shows a state where the cooling block isbrought into contact with the buffer part and the heat of the bufferpart is discharged with the cooling block.

FIG. 6 is a front cross-sectional view showing an example of a solderingapparatus as the heat-bonding apparatus according to a third embodimentof the present invention.

FIG. 7 is a flowchart showing an example of a method of manufacturing asoldered product as a heat-bonded product according to a fourthembodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

This application is based on the Patent Application No. 2013-011040filed on Jan. 24, 2013 in Japan, the contents of which are herebyincorporated in its entirety by reference into the present application,as part thereof.

The present invention will become more fully understood from thedetailed description given hereinbelow. The other applicable fields willbecome apparent with reference to the detailed description givenhereinbelow. However, the detailed description and the specificembodiment are illustrated of desired embodiments of the presentinvention and are described only for the purpose of explanation. Variouschanges and modifications will be apparent to those ordinary skilled inthe art on the basis of the detailed description.

The applicant has no intention to give to public any disclosedembodiment. Among the disclosed changes and modifications, those whichmay not literally fall within the scope of the patent claims constitute,therefore, a part of the present invention in the sense of doctrine ofequivalents.

With reference to the drawings, some embodiments of the presentinvention will be described hereinafter. In each drawing, the membersidentical with or corresponding to each other are given with the same orsimilar reference numerals, and the redundant description may not berepeated.

In the embodiment of the invention of the present application, the term“heat-bonding” broadly refers to bonding of workpieces by heating andcooling a bonding material and typically to bonding of workpieces byheating/melting and cooling/solidifying the bonding material. Theheat-bonding includes brazing and soldering with metal bonding materialsand bonding and welding with resin bonding materials or glass bondingmaterials. In the following embodiment as an example of the heat-bondingapparatus, a soldering apparatus in which a solder that is called assoft brazing alloy in brazing is used as the bonding material forsoldering is described.

Referring to FIG. 1, a soldering apparatus 100 as the heat-bondingapparatus according to a first embodiment of the present invention isdescribed. The explanation is made mainly referring to FIG. 1A showing aheating state by the exemplary soldering apparatus 100 and appropriatelyto FIG. 1B showing a heat discharging state (cooling state) as well.Also, the plots in FIG. 4 showing operating conditions of the solderingapparatus 100 for the description on the temperature control andpressure reducing control of the soldering apparatus 100 are referredto. The soldering apparatus 100 is a vacuum soldering apparatus providedwith a vacuum chamber 10 in which the pressure in the space housing theobject to be soldered (workpiece) 1 is reduced to a vacuum and theobject 1 is soldered in the vacuum. During soldering in the vacuum, theformation of an oxide film on the surface of solder can be prevented.Thus, highly reliable soldering can be achieved with a higher bondingstrength and an excellent electrical conductivity and without blockingof soldering due to the oxide film.

In addition, in case of soldering under vacuum, any flux is not requiredto be added to solder as a reducing agent for preventing the formationof the oxide film. Further, a flux removing process, following thesoldering process, for cleaning and removing the flux that remains onthe object 1 and having a possibility of inhibiting electricalconductivity can be eliminated. Additionally, the soldering apparatus100 for soldering in the vacuum does not require to fill the vacuumchamber 10 with a reducing gas, unlike conventional soldering apparatusin which soldering is conducted in an atmosphere of the reducing gassuch as hydrogen gas or formic acid gas (see Claim 1 of Patent Document1, for example). Above all, the soldering can be conducted without usingthe combustible hydrogen gas, the reducing gas, that requires carefulhandling. Accordingly, the soldering apparatus 100 has an advantage ofbeing able to effectively and easily perform the reliable soldering.

FIG. 1A and FIG. 1B are front cross-sectional views as seen from aconveying direction of a conveyor line for the objects 1 to be soldered,which are directed from the back side of the drawing sheet toward thefront side thereof. Walls of the vacuum chamber 10 are cut at theposition where heat detection parts of an object temperature sensor 40and a buffer temperature sensor 60 are disposed, and the cross sectionof the walls is shown in the drawing. An exhaust outlet 14 of the vacuumchamber 10 is connected to a vacuum pump 80 for discharging air insidethe vacuum chamber 10 (hereinafter, appropriately referred to as the“chamber interior”). The vacuum pump 80 can discharge air in the chamberinterior to the outside of the vacuum chamber 10 to arbitrarily reducethe pressure of the chamber interior to a vacuum (pressure lower thanatmospheric pressure) or a high vacuum. The vacuum pump 80 can produce amedium vacuum of about 7 to 133 Pa (about 50 to 1000 mTorr) in thechamber interior. The pressure in the chamber interior can be detectedwith a pressure gage 81 that is disposed so as to have a pressuredetecting section in the chamber interior. The value of the pressure inthe chamber interior is transmitted to a controller 50 (see FIG. 3) forcentrally controlling the operation of the soldering apparatus 100described later and used for adjusting actuation of the vacuum pump 80.The exhaust outlet 14 is disposed to be openable and closable inaccordance with control commands from the controller 50 and operated tobe opened during the actuation of the vacuum pump 80 and closed for theperiods other than the actuation period.

Gate valves 70 a (see FIG. 2) as vacuum breakers 70 described later aredisposed in a pair of the walls that transverses the conveyor line ofthe objects 1 among a plurality of walls provided in the vacuum chamber10. Each gate valve 70 a is disposed to be openable and closable inorder to transfer the objects 1 into the chamber interior along theconveyor line and to transfer the objects 1 out of the chamber interior.The gate valve 70 a is actuated by an air cylinder (not shown) connectedthereto and slidingly opened and closed in the direction vertical to thehorizontal direction. The gate valve 70 a is also disposed to close thechamber interior air-tightly so as to be able to reduce the pressure ofthe chamber interior to the vacuum when the gate valve 70 a is closed.The gate valve 70 a is operated and regulated by the controller 50 (seeFIG. 3) as described later. Thus, the controller 50 can operate andregulate to arbitrarily select sealing (closing) of the vacuum chamber10 and vacuum break (pressure recovery) of the vacuum inside thechamber.

The wall of the vacuum chamber 10 for separating the chamber interiorfrom the outside atmosphere is made of stainless steel with relativelyhigh thermal insulation properties. Thus, the chamber interior in whichthe object 1 is subjected to heat treatment can be thermally insulatedfrom the outside atmosphere, and the object 1 can be solderedefficiently therein. The plurality of partition walls in the vacuumchamber 10 are provided with transparent view windows 12 ofheat-resistant glass. Consequently, the operating condition of theapparatus and the soldering condition of the object 1 can be visuallymonitored even in operation of the soldering apparatus 100.

The object 1 to be soldered is placed on a placing carriage table 5 a asa placing table 5. The placing carriage table 5 a is disposed as a flatplate made of metal. The placing carriage table 5 a on which the object1 is put is placed on a plurality of conveying rollers 11 provided inthe soldering apparatus 100. The plurality of conveying rollers 11 formthe conveyor line for the object 1 in the soldering apparatus 100. Theplacing carriage table 5 a is made of copper that has a high thermalconductivity. In this case, the object 1 can efficiently be heated orcooled for heat treatment thereof through the placing carriage table 5 aas described later. The placing carriage table 5 a may be made of anyother metals such as a copper alloy as long as they have a high thermalconductivity. In this embodiment, the plural (2 columns and 3 rows, 6 intotal, for example (see the side view shown in FIG. 2 as well)) objects1 to be soldered are arranged on the placing carriage table 5 a. In suchcase, the plural objects 1 can simultaneously be subjected to heattreatment and efficiently soldered. The plurality of conveying rollers11 that form the conveyor line in the soldering apparatus 100 feed theobject 1 to a soldering position (heating/cooling position) shown in thedrawing by placing the placing carriage table 5 a thereon and rotatingto load the object into the soldering apparatus 100.

The object 1 to be soldered typically includes an electronic component 2and a substrate 3. The object 1 is typically soldered such that soldersuch as film solder (or cream solder is also applicable) is placed onthe substrate 3, then the electronic component 2 is placed on the filmsolder, and the object 1 is heated and cooled in this condition. Insoldering by the soldering apparatus 100, the solder is heated to thetemperature higher than the solder melting temperature (melting point)T_(m) (see FIG. 4A) (300 degrees Celsius, for example) in the vacuum,and then the melted solder is cooled and becomes solidified again, andthus the electronic component 2 and the substrate 3 are joined(soldered) to each other at a solder joint part 4. The electroniccomponent 2 generally refers to electronic components including asemiconductor package and surface-mounted chip resistor and chipcapacitor, which are fixed on/brought into electric continuity with thesubstrate 3 by soldering.

The soldering apparatus 100 according to this embodiment includes aplurality of thermal radiation heaters 20 a as a heater 20. The thermalradiation heater 20 a is disposed in a straight line and has a circularcross section (cylindrical rod shape) (see also the side view shown inFIG. 2). In this embodiment, the thermal radiation heater 20 a isdisposed to not heat directly the object 1 to be soldered but to heatthe placing carriage table 5 a that is the placing table 5 as a bufferpart. The buffer part serves as a thermal buffer part when the object 1is heated by the thermal radiation heater 20 a. The buffer parttypically has higher heat capacity than that of the object to besoldered and interposes between the heater and the object. On the otherhand, since the buffer part has higher heat capacity, residual heat maybe applied to the object even after the heater stops heating. In thisembodiment, a cooler 30 is provided to prevent redundant heating. Thus,the buffer part can protect the heat-sensitive object to be solderedfrom thermal destruction due to overheating.

The buffer part can also equalize the heating by the heater in terms oftime and space and transfer the heat to the object. Thus, the object canbe prevented from being thermally deformed (thermally bent) due tounequal heating when the heat is applied through the buffer part. Thethermal deformation of the object can be prevented by heating the objectthrough the buffer part that is arranged to come into contact with theobject. That is to say, a good contact state between the object and thebuffer part can be maintained.

A halogen heater is provided as the thermal radiation heater 20 a. Thethermal radiation heater 20 a is provided such that a thermal radiationpart including a thermal radiation filament made of tungsten is coveredwith a thermal radiation part sealing tube made of silica glass. Thethermal radiation part sealing tube encapsulates an inert gas (such asnitrogen or argon gas) and a halogen gas (such as iodine or brominegas). When the halogen heater is provided as the thermal radiationheater 20 a, the thermal radiation heater 20 a can withstand abrupttemperature rise/drop because of a halogen cycle between the halogen andthe tungsten. Thus, the temperature of the tungsten filament (thermalradiation part) can be raised at a high temperature exceeding 2700degrees Celsius in a few seconds after energization. Accordingly, thethermal radiation heater 20 a can rapidly heat the placing carriagetable 5 a facing thereto by heat radiation from the thermal radiationpart that becomes a high temperature. In addition, the thermal radiationheater 20 a can keep the lifetime of the tungsten filament long enoughbecause of the halogen cycle. Thus, the placing carriage table 5 can beheated rapidly, and the thermal radiation heater 20 a that has a higheconomical productivity and good characteristics can be realized.

The heating in a vacuum through heat radiation from the thermalradiation heater 20 a is not blocked by the vacuum. Thus, the thermalradiation heater 20 a can efficiently apply heat to the placing carriagetable 5 a from a heating position set apart from the placing carriagetable 5 a. The heat radiation from the thermal radiation heater 20 a,the halogen heater, includes infrared radiation having a wide wavelengthrange from a near-infrared wavelength range (approx. 0.75-approx. 4 μm)to a far-infrared wavelength range (approx. 4 μm-approx. 1 mm). Theplacing carriage table 5 a is heated by the heat radiation from thethermal radiation heater 20 a, and the object 1 placed on the placingcarriage table 5 a is indirectly heated by the heat transferred from theplacing carriage table 5 a.

When the temperature of the heated object 1 reaches a specified controltarget temperature T_(T2) (see FIG. 4A), heating the object 1 isachieved. The specified control target temperature T_(T2) is set to be aslightly higher (for example, higher by 25 degrees Celsius) than thesolder melting temperature (melting point) T_(m) (see FIG. 4A) in orderto ensure good soldering. The thermal radiation heater 20 a can heat thesolder joint part 4 of the object 1 to, for example, 220-400 degreesCelsius in accordance with the solder melting temperature (meltingpoint) T_(m), within the range of heating temperature in which theobject 1 is not brought to thermal destruction. In the exemplarysoldering apparatus 100, the heating temperature of the solder jointpart 4 (control target temperature T_(T2) of electronic component 2) canbe set to 325 degrees Celsius, for example, in order to solder thesolder joint part 4 using the solder that contains a higher content oflead component. The details on the control of heating the placingcarriage table 5 a by the thermal radiation heater 20 a are describedlater.

The soldering apparatus 100 is provided with the cooler 30 for coolingthe placing carriage table 5 a that has been heated with the thermalradiation heater 20 a described above. The thermal radiation heater 20 aand the cooler 30 according to this embodiment are disposed within thesame vacuum chamber 10. According to the arrangement described above,the objects 1 placed at the same loading positions within the samevacuum chamber 10 can be subjected to heat treatment through successiveheating and cooling without transferring the object 1 (and the placingcarriage table 5 a). In this case, the processing time required for thesoldering as the heat-bonding of the object 1 can be reducedsignificantly.

The cooler 30 has a cooling block 30 a and an air cylinder 30 b as adrive unit for driving the cooling block 30 a. The cooling block 30 a issupported by a plurality of guide posts 15 and driven by the aircylinder 30 b so as to move close to or away from the placing carriagetable 5 a. A coolant circulating circuit 30 c (see FIG. 1B) is providedinside the cooling block 30 a for circulating cooling water as thecoolant that cools the cooling block 30 a. When water is used as thecoolant, water can easily be used or disposed of as compared with thecase where another coolant is used. The cooling water circulating in thecoolant circulating circuit 30 c is supplied by a coolant supplying unit90 (see FIG. 1B) having a feed pump. The heat drawn from the coolingblock 30 a by the cooling water circulating in the coolant circulatingcircuit 30 c is dissipated into the atmosphere from radiator platesprovided in the coolant supplying unit 90. The coolant for cooling thecooling block 30 a may be any cooling liquids or gases as well as thecooling water. For example, a refrigerant that cools through latent heatof vaporization may be used in a direct manner. In addition, the coolingwater may be circulated in the coolant circulating circuit 30 c justonce and disposed of after one circulation without being circulated inthe coolant circulating circuit 30 c repeatedly. In this case, thesoldering apparatus 100 can be provided more easily. The adjustment forcooling the cooler 30 by means of the coolant supplying unit 90 isdescribed later in detail.

The cooling block 30 a may be made of copper that has a high thermalconductivity. In this case, the heat of the placing carriage table 5 acan efficiently be discharged with the cooling block 30 a. The coolingblock 30 a may be made of any other metals, such as the copper alloy,having a high thermal conductivity. The cooling block 30 a may beprovided such that copper plates as cooling plates are inserted (fitted)into fitting grooves (not shown) formed in a base part of the coolingblock 30 a or that a plurality of cooling plates and a cooling base isshaped from a solid copper block through deep grooving by a millingmachine.

The cooling block 30 a is typically disposed adjacent to the thermalradiation heater 20 a. When the cooling block 30 a is disposed asdescribed above, the cooling block 30 a comes into contact with thevicinity of a heat applying part of the placing carriage table 5 aheated by the thermal radiation heater 20 a, and thus the heat of theplacing carriage table 5 a can efficiently be discharged with thecooling block 30 a. In addition, guide pins 31 are provided at both endsof the cooling block 30 a. In the case where the guide pins 31 areprovided as described above, the placing carriage table 5 a can be movedand positioned with the guide pins 31 fitted into correspondingpositioning holes formed in the placing carriage table 5 a when thecooling block 30 a is driven. Thus, the cooling plate of the coolingblock 30 a and the placing carriage table 5 a can be positioned relativeto each other. Because the cooling plate can correctly be positionedwith respect to the heat applying part of the placing carriage table 5 aand come into contact with a specified cooling region of the placingcarriage table 5 a accordingly, the heat of the placing carriage table 5a can efficiently be discharged. When the positioning is conducted asdescribed above using the guide pins 31, the placing carriage table 5 aand the object 1 can be prevented from deviating from specifiedarrangement positions due to the abutment of the cooling block 30 aagainst the placing carriage table 5 a. Thus, an object temperaturesensor 40 and a buffer temperature sensor 60 included in the solderingapparatus 100 described below can accurately detect the temperatures ofthe object 1 to be soldered and the placing carriage table 5 a which arecorrectly arranged in the specified positions.

The cooling block 30 a is formed in a comb shape so that each of thethermal radiation heaters 20 a can be disposed between two comb teeth.Each comb tooth of the cooling block 30 a is formed in the shape of aflat plate. The comb has a specified thickness and arranged such thatthe thickness direction is oriented in the horizontal direction. Inother words, the front side and the back side are arranged in thehorizontal direction. One end face of the flat plate which is normal tothe front side and the back side is arranged in the horizontal directionand forms an upper end face (contact face) of the cooling block 30 a.The lower end (face) opposite to the upper end face is integrallyconnected to the base of the cooling block 30 a in which the coolantcirculating circuit 30 c (see FIG. 1B) is provided. The specifiedthickness is determined in accordance with the size of the object 1 tobe soldered. An appropriate thickness of a comb tooth is 0.2-0.6 times,preferably 0.3-0.5 times, of the arrangement interval with which aplurality of the thermal radiation heaters 20 a are arranged.

Temperature of the objects 1 is indirectly regulated by the coolingblock 30 a through the placing carriage table 5 a as is the case withheating by the thermal radiation heater 20 a. In this case, thetemperature of the objects 1 is regulated by the cooling block 30 athrough temperature equalization with the placing carriage table 5 a interms of time and space. When the temperature of the objects 1 isregulated through the placing carriage table 5 a as described above, thetemperature of the objects 1 can be uniformly regulated, unlike the casewhere the placing carriage table 5 a as the buffer part is not provided.

The cooling block 30 a discharges the heat from the placing carriagetable 5 a through heat transfer when abutting against (coming intocontact with) the placing carriage table 5 a. A drive unit 30 b fordriving the cooling block 30 a adjusts the approach and the separationof the cooling block 30 a to and from the placing carriage table 5 a.The drive unit 30 b is driven in accordance with control commands from abuffer temperature adjusting part 55 c-1 (see FIG. 3B) included in thecontroller 50 described later in detail. Thus, the controller 50 canadjusts the approach and the separation of the cooling block 30 a to andfrom the placing carriage table 5 b heated by the thermal radiationheater 20 a. In other words, the controller can adjusts the approach andthe separation of the cooling block to and from the buffer part heatedby the heater. The term “to adjust the approach and the separation”herein refers to a concept including “to make contact by approaching andto keep a distance by moving away” and “to adjust a distance between thebuffer part and the cooling block”. The cooling block is typicallydriven to move to either one of two positions which are a contactposition where the cooling block comes into contact with the buffer partand a spaced position where the cooling block is spaced apart from thebuffer part, and adjusts the time for which the cooling block is kept atthe contact position and the spaced position. Thus, the cooling blockcan control the temperature of the object to be soldered as describedlater.

The cooling block 30 a is put on standby at the spaced position (seeFIG. 1A) apart from the placing carriage table 5 a when the thermalradiation heater 20 a applies heat to the object 1 by heating theplacing carriage table 5 a. On the other hand, the cooling block isdriven to move in the vertical direction toward a lower face of theplacing carriage table 5 a to the contact position (see FIG. 1B) incontact with the placing carriage table 5 a in accordance with thecommands from the controller 50 described below in detail when theobject 1 is to be cooled through the placing carriage table 5 a. Thethermal radiation heater 20 a and the cooling block 30 a are bothprovided so as to face and adjacent to the object 1 and the placingcarriage table 5 a; however, those are provided such that respectivedistances from the heater 20 a and the cooling block 30 a to the object1 and the placing carriage table 5 a can be independently different fromeach other. That is to say, the thermal radiation heater 20 a and thecooling block 30 a are provided so as to be capable of relativemovement, and those are not fixed as one unit. In addition, an upperface of the cooling block 30 a is formed in the comb shape as describedabove, and thus the cooling block 30 a does not interfere with theplurality of the thermal radiation heaters 20 a when the cooling block30 a is driven by the drive unit 30 b to move toward the placingcarriage table 5 a. The comb teeth of the cooling block 30 a protrudefrom between the plurality of the thermal radiation heaters 20 a to comeinto contact with the placing carriage table 5 a (see FIG. 1B).

In the case that the cooling block is provided as described above, theheight of the cooling block 30 a (the length of a comb tooth part) isset to a specified height, and thus the placing carriage table 5 a andthe thermal radiation heater 20 a can be spaced each other at aspecified distance. The thermal radiation heater 20 a is fixedlyinstalled and arranged as described above so as to be spaced at thespecified distance from and heat the placing carriage table 5 a (seeFIG. 1A). The separation distance for heating is set so that the heatradiation from the thermal radiation heater 20 a can moderately bediffused to uniformly cover and heat the entire lower face of theplacing carriage table 5 a. Thus, the object 1 can be heated mostefficiently at the heating position (separation distance). On the otherhand, the placing carriage table 5 a is arranged so as to be moved fromthe heating position (optimum separation distance from the thermalradiation heater 20 a) by the cooling block 30 a when cooled. As shownin FIG. 1B, the placing carriage table 5 a is moved away from thethermal radiation heater 20 a, for example. In addition, the thermalradiation heater 20 a is positioned at a base part of the comb tooth ofthe cooling block 30 a, and the heat radiation is blocked fromdiffusing, by the comb tooth. The thermal radiation heater 20 a has atendency to continue to heat the placing carriage table 5 a withresidual heat even after electrical heating is stopped, as describedlater in detail. In this case, the comb tooth of the cooling block 30 aallows the placing carriage table 5 a to move from the optimum heatingspacing and can reduce the diffusion of the heat radiation from thethermal radiation heater 20 a to a minimum. Thus, the heating efficiencyof the placing carriage table 5 a by the thermal radiation heater 20 acan be reduced, and the cooling efficiency of the placing carriage table5 a and the object 1 can be enhanced.

In the soldering apparatus 100, the cooling block 30 a lifts up theplacing carriage table 5 a from the conveying roller 11 entirely asshown in FIG. 1B when the cooling block 30 a most closely comes intocontact with the placing carriage table 5 a. At that time, the mostintimate contact state between the cooling block 30 a and the placingcarriage table 5 a is attained by means of the weight of the object 1and the placing carriage table 5 a, that is, the contact position wherethe cooling block comes into contact with the buffer part. The detailson the control of heat discharge (cooling) from the placing carriagetable 5 a by the cooling block 30 a are described later.

The vacuum soldering apparatus for soldering in a vacuum blocking theheat transfer has particular technical problems. The inventors of thepresent application found that the following phenomena are main causesof overheating of the object to be soldered. (1) Natural cooling of theobject (heat transfer to atmosphere by convection from the object)cannot be expected in the vacuum. (2) Once the buffer part such as theplacing table in contact with the object is heated, the object iscontinuously heated by the heat transfer or heat radiation ofaccumulated heat even after the heater is turned off. (3) A vacuum isinterposed at least partially between the buffer part and the object,and the heat transfer is blocked due to the vacuum. In the vacuum, adecrease in (blockage of) the heat transfer due to the vacuum causesdifference in heating state between the buffer part and the object.Thus, the buffer is kept at an excessively high temperature in somecases even after the object is heated to a target temperature to besoldered. This phenomenon is particularly noticeable when the heating isrequired in a hurry in order for the cycle time to be shortened. Theheat is finally transferred to the object through heat transfer due toheat radiation between the buffer part and the object and heatconduction through a contact part between the buffer part and theobject. Due to such heat transfer, the temperature of the object mayovershoot (the object may be overheated) from the target temperatureappropriate to the soldering.

In addition, the inventors of the present application found that theobject may be overheated, when the vacuum in the vacuum chamber isbroken, due to quick recovery of heat transfer through atmospherebetween the object to be soldered and the buffer part such as theplacing table which is brought into contact with the object. Thisproblem arises from a large temperature difference between the objectand the buffer part due to the buffer part being heated in a state wherethe heat transfer between the object and the buffer part is reduced in avacuum. Then, the heat transfer through atmosphere is regained due tothe vacuum break in the state where the object and the buffer part havethe temperature difference. The object is rapidly heated by the hotbuffer part thereafter. The object becomes overheated through thisheating. As described above, the heat accumulated in the buffer partheated to a high temperature in a thermally insulated state by thevacuum rapidly flows into the object due to the vacuum break and causesoverheating of the object. It has been obscure in a conventional artthat the overheating of the object is caused by the large temperaturedifference between the buffer part and the object during the solderingin a vacuum as described above.

On the other hand, the vacuum break contributes to the recovery of heatdissipation (thermal diffusion) to the atmosphere such as ambient aircirculating by convection from the heated object and buffer part and thecooling of the object. Thus, in the case that the vacuum break isconducted in the earliest possible stage within the condition rangeswhere the object is not overheated due to the vacuum break describedabove, the object can be prevented from overheating and cooled in a lesstime. The soldering apparatus according to the invention of the presentapplication is configured based on important findings in the vacuumsoldering apparatus by the inventors of the present application.

The soldering apparatus 100 includes the object temperature sensor 40for detecting the temperature T_(D) of the object 1 to be soldered (seeFIG. 4A). The object temperature sensor 40 is provided as a radiationthermometer that can detect the temperature (heat radiation temperature)T_(D) of the object 1 without being blocked by the vacuum even in thevacuum. The object temperature sensor 40 detects the temperature T_(D)of the electronic component 2 that is the most heat-sensitive componentamong the electronic component 2, the substrate 3, and the solder jointpart 4 which form the object 1 to be soldered and sends the temperatureto the controller 50. In the case where the temperature is controlledthrough the detection of the temperature T_(D) of the mostheat-sensitive electronic component 2 among the plurality of componentsforming the object 1, the object 1 can be prevented from beingoverheated in the safest way.

The object temperature sensor 40 according to this embodiment isprovided so as to detect the temperature of only the most heat-sensitiveobject 1 among the plural (six) objects 1 to be soldered placed on theplacing carriage table 5 a and control the temperature for the heattreatment. In other words, the object temperature sensor 40 is providedso as to detect the temperature of the most heat-sensitive object 1(electronic component 2) only and control the temperature of the entiresoldering apparatus 100 for soldering six objects 1. The structuredescribed above can eliminate the need for the detection of thetemperature of the other plural (five) objects 1 to be soldered(electronic components 2) that are relatively resistant to heat. Thus,the soldering apparatus 100 can be provided more easily.

The soldering apparatus 100 includes the controller 50 for adjusting theheat application by the thermal radiation heater 20 a and the heatdischarge (cooling) by the cooling block 30 a to control the temperatureT_(D) of the object 1 based on the temperature T_(D) of the object 1(see FIG. 4A) detected by the object temperature sensor 40. Thecontroller 50 is a control computer that is provided to be programmablefrom an external source.

Referring now to FIG. 3A and FIG. 3B, the controller 50 is described.FIG. 3A is a block diagram showing functional parts included in thecontroller 50, and FIG. 3B is a block diagram showing the details of thefunctional parts included in a control part 55 of the controller 50. Thecontroller 50 is provided so as to be capable of controlling operationsof the soldering apparatus 100 in an integrated and centralized manner.The controller 50 includes the control part 55 for unifying the controland the operations performed by the controller 50 and a centralprocessing unit 51 for processing information thereof. In addition, thecontroller 50 includes a plurality of operating parts (such as a heateroperating part 52, for example) for independently operating actuatingparts of the soldering apparatus 100.

Referring to FIG. 3B, the control part 55 included in the controller 50is described. The control part 55 includes a set value memory unit 55 athat stores control target values in advance for temperature control ofthe soldering apparatus 100. The control target values are temperaturetarget values such as a first control target temperature T_(T1) and asecond control target temperature T_(T2) (see FIG. 4A), for example. Theset value memory unit 55 a also stores drive setting values (such as aspecified drive amount and driving speed, for example) for use in theoperations of the actuating parts of the soldering apparatus 100. Theset value memory unit 55 a is typically provided as an informationstorage circuit (memory). The control part 55 reads the control targetvalues and the drive setting values that are previously stored in theset value memory unit 55 a when necessary. The control part 55 sets theread control target value as the control value of an object temperaturecontrol part 55 c included in the control part 55. The control part 55also sets the read drive setting values as respective dive settingvalues of a pressure-reducing operation part 55 b and a vacuum breakingoperation part 55 d that are included in the control part 55.

The object temperature control part 55 c adjusts the actuating parts ofthe soldering apparatus 100 by means of the buffer temperature adjustingpart 55 c-1 and a vacuum adjusting part 55 c-2 that are included in theobject temperature control part 55 c so as to achieve the set controltarget values. Specifically, the buffer temperature adjusting part 55c-1 operates the heater operating part 52, a cooler operating part 53,and a coolant supplying unit operating part 59 (see FIG. 3A for eachcomponent) for adjustment thereof. In addition, the vacuum adjustingpart 55 c-2 operates a vacuum breaker operating part 57 and a vacuumpump operating part 58 (see FIG. 3A for each component) to conduct theadjustment.

The pressure-reducing operation part 55 b operates the vacuum breakeroperating part 57 and the vacuum pump operating part 58 (see FIG. 3A foreach component) so as to conduct a specified pressure-reducing operationby using the dive setting values that have been set. Furthermore, thevacuum breaking operation part 55 d operates the vacuum breakeroperating part 57 so as to conduct a specified vacuum breaking operationby using the dive setting value that has been set. The control part 55is provided so as to be capable of storing the control target valuesthat have been set and the records of driving operations and adjustmentsof the soldering apparatus 100 as control/operation history along timeseries. The temperature control performed by the object temperaturecontrol part 55 c and the pressure-reducing operation and the vacuumbreaking operation performed by the pressure-reducing operation part 55b and the vacuum breaking operation part 55 d are described later indetail.

With reference to FIG. 3A, the operating parts included in thecontroller 50 are described. The heater operating part 52 is provided soas to be capable of energizing/stopping the energization of or adjustingthe output of thermal radiation heater 20 a (see FIG. 1A). The cooleroperating part 53 is provided so as to be capable of changing andadjusting a driving position of the air cylinder for driving the coolingblock 30 a of the cooler 30 (see FIG. 1A, 1B). The object temperaturesensor operating part 54 operates the object temperature sensor 40 (seeFIG. 1A) so that the object temperature sensor outputs detectedtemperature information of the temperature T_(D) of the object (see FIG.4A) to the controller 50 with a specified sampling frequency.

The buffer temperature sensor operating part 56 to be described later indetail is also provided so as to be capable of operating the buffertemperature sensor 60 (see FIG. 1) in the same manner as the objecttemperature sensor operating part 54. The vacuum breaker operating part57 changes and adjusts the driving position of the air cylinder fordriving the gate valve 70 a (see FIG. 2) and also drives a gas supplyapparatus 70 b (see FIG. 1A), a gas supply pump described later indetail, (and adjusts the flow rate) and opens and closes an inlet port13 (see FIG. 1A). The vacuum pump operating part 58 drives (and adjuststhe emission volume of) the vacuum pump 80 (see FIG. 1A) and also opensand closes an exhaust port 14 (see FIG. 1A). The control part 55 canoperate the pressure gage 81 (see FIG. 1A) for detecting the pressure ofthe chamber interior so that the pressure gage outputs detected pressureinformation to the control part 55 with a specified sampling frequency.The coolant supplying unit operating part 59 is provided so as to becapable of driving a coolant supplying pump (not shown) (and adjustingthe flow rate) and operating thermometer (not shown) to detect thetemperature of the coolant.

Returning to FIG. 1A, 1B, the description continues further. In thisembodiment, the object temperature control part 55 c (see FIG. 3B)included in the controller 50 adjusts thermal radiation heater 20 a sothat the heater radiates heat with a constant heat radiation output. Theconstant heat radiation output is determined such that the object 1 tobe heated through the placing carriage table 5 a is heated with apredetermined temperature rise rate (temperature (Degree C))/time(sec.)). The temperature rise rate of the object 1 at that time can bedetermined in accordance with capacity of the temperature control suchas heat capacities of the placing carriage table 5 a and the object 1,response speed of the temperature control, and an error so that thetemperature T_(D) of the object 1 (see FIG. 4A) can be controlledthrough cooling after heating. For example, the temperature rise rate ofthe object 1 is selected so that the maximum temperature rise rate isachieved within the range in which the temperature can be controlledafter heating. In this embodiment, the object temperature control part55 c included in the controller 50 substantially turns on/off thermalradiation heater 20 a for adjusting. Thermal radiation heater 20 astarts to heat the placing carriage table 5 a (and the object 1) througha heating starting operation by the heater operating part 52 (see FIG.3A) with the specified heat radiation output previously recorded in theset value memory unit 55 a of the controller 50 (see FIG. 3B).

In this embodiment, the placing carriage table 5 a (and the object 1) isheated under atmospheric pressure without reduction in pressure of thechamber interior. When the placing carriage table 5 a is heated underthe atmospheric pressure, the heat transfer between the placing carriagetable 5 a and the object 1 is not blocked by the vacuum. The temperatureincrease (rise) of the object by heat transfer gets significantly behindthe temperature rise of the placing carriage table 5 a in terms of timebecause of heat transfer time required for heat transfer and heatconduction (see FIG. 4A). However, when the heating is conducted underthe atmospheric pressure, no large difference in heating temperaturesachieved by the placing carriage table 5 a and the object 1 is made, andboth the placing carriage table 5 a and the object 1 can be heated tothe first control target temperature T_(T1) that is approximately equalto each other (see FIG. 4A). The controller 50 is preferably operated soas to air tightly seal the vacuum chamber 10 in which the object 1 isloaded in advance before starting to heat with thermal radiation heater20 a. The vacuum chamber 10 can be sealed through the operation of thegate valve 70 a (see FIG. 2) by means of the vacuum breaker operatingpart 57 (see FIG. 3A) included in the controller 50. In this case, theheating by thermal radiation heater 20 a can efficiently be conductedinside the well-insulated and sealed chamber. In addition, thisembodiment is safe because thermal radiation heater 20 a does not applya large amount of heat to an exterior of the vacuum chamber 10.

The object temperature control part 55 c (see FIG. 3B) included in thecontroller 50 suspends the heating by thermal radiation heater 20 a whenthe temperature T_(D) of the object 1 (see FIG. 4A) reaches thespecified first control target temperature T_(T1) (see FIG. 4A) lowerthan the melting temperature (melting point) T_(m) of the solder (seeFIG. 4A). This is because the pressure of the chamber interior isreduced to reach a vacuum before the solder melts and an oxide film isprevented from being formed on the surface of the solder. In the casewhere the pressure of the chamber interior is reduced to a vacuum beforethe solder melts, the solder melts in the vacuum, and a conducting pointbetween the electronic component 2 and the substrate 3 gets wet by thesolder, the soldering of the conducting point is not blocked by theoxide film. In this case, good soldering can be achieved which has goodelectrical conductivity and strong mechanical fixation. The controller50 allows the set value memory unit 55 a (see FIG. 3B) included in thecontrol part 55 to store the record of the melting temperature (meltingpoint) T_(m) of the solder. In this embodiment, the heating is suspendedwhen the detected temperature T_(D) of the object 1 reaches the firsttarget temperature T_(T1) (280 degrees Celsius) lower by 20 degreesCelsius than the melting point T_(m) of the solder that is 300 degreesCelsius.

In this embodiment, the pressure of the chamber interior is not reducedimmediately after the object 1 is heated to the first heating targettemperature T_(T1) (see FIG. 4A) by thermal radiation heater 20 a, butthe placing carriage table 5 a and the object 1 are placed in theatmosphere, and the heat transfer waiting time is set for waiting theheat transfer in order for the temperature equalization to be spreadover the entire component (see FIG. 4A). The configuration as describedabove can ensure the heat transferring time required to adequatelyconduct the efficient heat transfer from the placing carriage table 5 ato the object 1 in the atmosphere having a high rate of heat transfer(heat transfer rate). Thus, the temperature of every part of the placingcarriage table 5 a and the object 1 can be brought to the equal anduniform first target temperature T_(n). As described above, the pressureof the chamber interior is reduced in a state where the temperature ofevery part of the placing carriage table 5 a and the object 1 isadequately equalized.

As described above, because thermal diffusion (natural cooling) from theobject 1 and the placing carriage table 5 a to the atmosphere is blockedwhen the pressure of the chamber interior is reduced toward reach thevacuum, the object 1 may be overheated. Thus, the controller 50 startsto control the temperature of the object 1 by having the buffertemperature adjusting part 55 c-1 (see FIG. 3B) adjust the heatdischarge (cooling) by the cooling block 30 a before reducing thepressure of the chamber interior. The adjustment of the heat discharge(cooling) by the cooling block 30 a is performed through a change in theamount of discharged (cooled) heat per unit time from the placingcarriage table 5 a. The controller 50 starts to drive the vacuum pump 80to reduce the pressure of the chamber interior through thepressure-reducing operation part 55 b (see FIG. 3B) after starting tocontrol the temperature of the object 1 through the adjustment of theheat discharge (cooling). The pressure of the chamber interior isreduced to the medium vacuum lower than 100 Pa through the discharge ofair by the vacuum pump 80 (see FIG. 4A).

In the heating by the heater 20 such as thermal radiation heater 20 a,the object 1 and the placing carriage table 5 a continues to be heatedby the residual heat liberated by a heat generating part such as aheating wire of the heater 20 heated to a high temperature even afterelectrical heating of the heater 20 terminates. In other words, heatingdoes not terminate even if energization of the heater 20 is terminated(turned off). Thermal diffusion from the heated object 1 and placingcarriage table 5 a to the atmosphere cannot be expected in a vacuum.Thus, the temperature control of the vacuum soldering apparatus forsoldering in a vacuum has a tendency to overshoot in which thetemperature T_(D) of the object 1 (see FIG. 4A) exceeds the controltarget temperature T_(T2) (see FIG. 4A) in comparison with the case inthe temperature control of the conventional soldering apparatus forsoldering in ambient air or a reducing gas atmosphere (see Claim 1 ofPatent Document 1, for example). Heating overshoot of the object 1 has apossibility of thermal destruction of the object 1 and causes anincrease in cooling time.

The conventional soldering apparatus in which the temperature iscontrolled by detecting the temperature of the placing table (see Claim1 and Claim 7 of Patent Document 1, for example) could not accuratelycontrol the temperature of the object in a vacuum. The conventionalsoldering apparatus was provided so that the soldering is performed inthe reducing gas atmosphere or ambient air to avoid a vacuum where theobject might be overheated. In the case where such a conventionalsoldering apparatus was used to solder in a vacuum, change in heattransfer (rate of heat transfer (heat transfer coefficient)) between theplacing table and the object associated with the pressure reduction ofthe chamber interior was left out of the control and not managed. Thus,in the case where the conventional soldering apparatus was used tosolder in a vacuum, heating overshoot of the object had to be preventedwhile imperfections in control were complemented. The amount of heatapplication by the heater had to be reduced, and the temperature riserate (Temperature (Degree C)/Time (sec.)) of the object had to bedecreased. The heating by the heater had to be terminated in the earlystages before the temperature of the object adequately rose incomparison with the melting point of the solder, and the object had tobe heated with the residual heat over time. In addition, the objectcould not be heated well to the heating target temperature required insoldering. As described above, in the case where the conventionalsoldering apparatus was used to solder in a vacuum, a long cycle timewas required. The object was subjected to thermal destruction due toimperfections in temperature control. On the contrary, due toinsufficient heating, inadequate soldering was performed in some cases.

On the other hand, the soldering apparatus 100 according to the presentapplication is provided to adjust heating and heat discharge (cooling)in a vacuum based on the detected temperature T_(D) of the object 1 tobe soldered (see FIG. 4A). Thus, the change in heat transfer (rate ofheat transfer (heat transfer coefficient)) between the placing table 5 aand the object 1 can be incorporated into the temperature control of theobject 1 and managed. Specifically, all of the changes in the heattransfer between the placing table 5 a and the substrate 3, the heattransfer between the substrate 3 and the solder joint part 4, and theheat transfer between the solder joint part 4 and the electroniccomponent 2 can be incorporated into the control and managed. Inaddition, the change in the heat transfer between the placing carriagetable 5 a and the cooling block 30 a when heat of the placing carriagetable 5 a is discharged (cooled) with the cooling block 30 a can beincorporated into the control and managed. Thus, the temperature can beadequately controlled during soldering in a vacuum. The configuration asdescribed above can achieve reliable heating and soldering of the object1 to the heating target temperature T_(T2) (see FIG. 4A) in a vacuum.The temperature T_(D) of the object 1 does not too much overshoot beyondthe heating target temperature T_(T2), and the object 1 is not subjectedto thermal destruction. The soldering can efficiently be performed in ashort cycle time.

In the soldering apparatus 100 according to this embodiment, the placingcarriage table 5 a is heated by the residual heat of thermal radiationheater 20 a. Thermal diffusion of the placing carriage table 5 a toambient air is also blocked in the vacuum of the chamber interior in thesame manner as the object 1. Thus, the temperature T_(B) of the placingcarriage table 5 a (see FIG. 4A) sharply rises after the pressure of thechamber interior is reduced toward a vacuum. That is to say, the placingcarriage table 5 a is heated to a high temperature instead of the object1. However, the placing carriage table 5 a is not subjected to thermaldestruction even if heated to a high temperature in contrast to theheat-sensitive object 1.

The heat of the placing carriage table 5 a is discharged (cooled) by thecooling block 30 a as described above. Thus, the excess heat amountexceeding the heat amount to be transferred to the object 1 by theplacing carriage table 5 a is drawn by the cooling block 30 a beforetransferred to the object 1. The temperature T_(B) of the placingcarriage table 5 a (see FIG. 4A) rises sharply and then drops, and thusthe temperature difference between the temperature T_(B) and thetemperature T_(D) of the object 1 (see FIG. 4A) becomes small. On theother hand, the temperature T_(D) of the object 1 is accuratelycontrolled to the specified target temperature T_(T2) (see FIG. 4A)through the heat discharge (cooling) adjustment by the cooling block 30a. The heat capacity of the placing carriage table 5 a is defined to bethe amount of heat capacity in which the placing carriage table canfunction as the buffer part.

The object temperature control part 55 c (see FIG. 3B) of the controlpart 55 included in the controller 50 drives the cooling block 30 a tocontrol the temperature of the object 1. The object temperature controlpart 55 c performs PID control(proportional-plus-integral-plus-derivative control) so that thetemperature T_(D) (see FIG. 4A) of the object 1 detected by the objecttemperature sensor 40 is to be the specified control target temperatureT_(T2) (see FIG. 4A). The melting temperature (melting point) T_(m) ofthe solder (see FIG. 4A) exemplified in this embodiment is 300 degreesCelsius, and the specified control target temperature T_(T2) is 325degrees Celsius which slightly exceeds the melting temperature T_(m). Inorder to achieve the control target temperature T_(T2), the buffertemperature adjusting part 55 c-1 (see FIG. 3B) included in the objecttemperature control part 55 c adjusts the heat discharge (cooling) ofthe placing carriage table 5 a by operating the cooling block 30 athrough the cooler operating part 53 (see FIG. 3A). As described above,the temperature control of the object 1 is conducted through theadjustment of contact time of the placing carriage table 5 a with thecooling block 30 a in this embodiment.

The control part 55 of the controller 50 (see FIG. 3B) is expected tocool the object 1 as soon as possible after the temperature T_(D) (seeFIG. 4A) of the object 1 detected by the object temperature sensor 40reaches the specified control target temperature T_(T2) (see FIG. 4A).In this case, a newly specified third control target temperature T_(T3)(not shown) can be changed to room temperature of 24 degrees Celsius,for example, in accordance with the control target temperatureinformation stored in the set value memory unit 55 a (see FIG. 3B)included in the control part 55. In order to cool the object 1 quickly,the object 1 is preferably cooled through natural cooling (atmosphere)by the immediate vacuum break of the chamber interior and recovery ofthermal diffusion from the object 1 to the atmosphere in addition to thecooling with the cooling block 30 a. However, the object may beoverheated due to the vacuum break as described above when there is atemperature difference between the temperature T_(B) of the placingcarriage table 5 a (see FIG. 4A) and the temperature T_(D) of the object1.

In this embodiment, the soldering apparatus 100 further includes thebuffer temperature sensor 60 for detecting the temperature T_(B) of theplacing carriage table 5 a (see FIG. 4A). The buffer temperature sensor60 is provided as a radiation thermometer that can detect thetemperature (heat radiation temperature) T_(B) of the placing carriagetable 5 a without blockage of the vacuum even in the vacuum. The buffertemperature sensor 60 detects the heat radiation temperature T_(B) at aspecified position located in the center of the placing carriage table 5a and transmits it to the controller 50. The temperature T_(B) of theplacing carriage table 5 a is uniform over the table, and thus thebuffer temperature sensor 60 may detect the temperature T_(B) at onearbitrary position in the placing carriage table 5 a.

In order to prevent the overheating of the object 1, the solderingapparatus 100 performs a vacuum break B (see FIG. 4A), considering heatinput acceptable to the heat-sensitive object 1 (electronic component2). In this case, the maximum temperature difference T_(O) (see FIG. 4A)between the placing carriage table 5 a and the object 1 can bedetermined in advance where the vacuum break B can be performed. Thecontroller 50 allows the set value memory unit 55 a (see FIG. 3B)included in the control part 55 to store the record of the specifiedtemperature difference T_(O) as a condition for the vacuum break B.Thus, the controller 50 can control to perform the vacuum break B afterthe temperature T_(D) of the object 1 (see FIG. 4A) reaches thespecified target temperature T_(T2) (see FIG. 4A) and at the earliestpossible time when the temperature difference between the placingcarriage table 5 a and the object 1 reaches the specified temperaturedifference T_(O) or below.

To perform the vacuum break B of the chamber interior (see FIG. 4A), thevacuum breaker operating part 57 (see FIG. 3A) included in thecontroller 50 operates and opens the gate valve 70 a (see FIG. 2) as thevacuum breaker 70 according to the command from the vacuum breakingoperation part 55 d (see FIG. 3B). Thus, the pressure inside the chamberrecovers rapidly to atmospheric pressure. In the case where thetemperature difference between the placing carriage table 5 a and theobject 1 is smaller than or equal to the specified temperaturedifference T_(O) (see FIG. 4A), the temperature rise of the object 1associated with the vacuum break B is small within an acceptable range(see FIG. 4A), and the object 1 is not damaged by heat. The temperaturedifference between the placing carriage table 5 a and the object 1 cangradually be eliminated through the vacuum breaking operation withfeedback control by means of the vacuum breaker 70 as described later indetail. A dedicated vacuum breaking valve (not shown) may be provided inplace of the gate valve 70 a. At that time, the vacuum break B can beperformed while the degree of vacuum is adjusted delicately. The gatevalve 70 a can easily open and close after the vacuum break B isperformed.

In addition, the vacuum break B of the chamber interior is determined tobe performed on the condition that the temperature T_(D) of the object 1(see FIG. 4A) detected by the object temperature sensor 40 is higherthan or equal to the melting temperature T_(m) of the solder (see FIG.4A). In the case described above, molten solder can solidifies underatmospheric pressure. The configuration as described above can crushvoids by applying the atmospheric pressure to the solder in the moltenstate even when the voids (cavities) develop in the solder joint part 4,and thus the solder does not solidify with the voids substantiallyremaining in the solder joint part 4. The voids are crushed at least insize (volume) that does not affect the quality of soldering. Thus,highly reliable soldering can be conducted with strong mechanicalbonding and excellent electrical conductivity.

As described in this embodiment, a void hardly develops in the solderjoint part 4 when the solder is heated in a vacuum to the meltingtemperature (melting point) T_(m) (see FIG. 4A), in comparison with theconventional soldering apparatus (see Claim 1 of Patent Document 1, forexample) for heating the solder to the melting temperature (meltingpoint) or above in the reducing gas atmosphere or ambient air.Furthermore, the pressure inside the void is under vacuum even when thevoid develops in the solder joint part 4 such as the contact facebetween the electronic component 2 or substrate 3 and the solder jointpart 4, and thus the void can be shrunk and crushed through restorationof the pressure inside the chamber to atmospheric pressure before thesolder solidifies. In the soldering with the soldering apparatus 100according to this embodiment, the void developing inside the solderjoint part 4 shrinks in volume as the pressure inside the chamberrestores atmospheric pressure.

In the conventional soldering apparatus, the void developing underatmospheric pressure may expand and burst in a vacuum, resulting frompressure reduction of the chamber interior after melting of the solderunder atmospheric pressure. In addition, the solder may scatter when thevoid expands and bursts in the conventional soldering apparatus.Scattering of the solder has a possibility of greatly deterioratingquality of soldered products. On the other hand, the soldering apparatus100 according to this embodiment melts the solder in a vacuum and thusprevents the void from expanding and bursting in a vacuum and the solderfrom flying apart unlike the conventional soldering apparatus and canperform good soldering.

The object 1 can be naturally cooled when the vacuum break B (see FIG.4A) is conducted, and thus the temperature T_(D) of the object 1 (seeFIG. 4A) drops sharply. The vacuum breaking operation part 55 d (seeFIG. 3B) included in the controller 50 typically moves the gate valve 70a (see FIG. 2) to perform the vacuum break B. Specifically, the gatevalve 70 a at a closed position is driven to slide to an open positionof the gate valve 70 a where the soldered object 1 can be transferredout of the chamber interior. The vacuum breaker operating part 57 (seeFIG. 3 A) operated by the vacuum breaking operation part 55 d operatesthe gate valve 70 a to drive it to the open position as fast as possiblewith the maximum transfer rate.

On the other hand, the vacuum breaking operation part 55 d (see FIG. 3B)can perform the vacuum break B (see FIG. 4A) so as to control thetemperature T_(D) of the object 1 (see FIG. 4A). The vacuum breakingoperation part 55 d can perform the temperature control of the object 1by adjusting the opening and closing of the gate valve 70 a (see FIG. 2)as the vacuum breaker 70 in accordance with the temperature T_(D) of theobject 1 detected by the object temperature sensor 40. When the gatevalve 70 a is opened to restore the pressure of the chamber interior,the heat transfer (rate of heat transfer (heat transfer coefficient))from the placing table 5 a to the object 1 through the atmosphere isregained. At that time, the rise rate of the temperature T_(D) of theobject 1 (Temperature (degree C.)/Time (sec.)) increases as timeelapsing, and the temperature T_(D) of the object 1 increases at anaccelerated rate. On the contrary, when the gate valve 70 a is closedagain, the restoration of the pressure of the chamber interior isdiscontinued, and regaining of the heat transfer (rate of heat transfer(heat transfer coefficient)) through the atmosphere is interrupted. Inthis case, the increase in the rise rate of the temperature T_(D) of theobject 1 is interrupted. The rise of the temperature T_(D) of the object1 gets slow at that time.

Furthermore, the controller 50 can perform the vacuum break B (see FIG.4A) with a combination of the pressure-reducing operation conducted bydriving the vacuum pump 80 and the vacuum breaking operation. The vacuumadjusting part 55 c-2 (see FIG. 3B) provided in the object temperaturecontrol part 55 c of the control part 55 included in the controller 50can reduce the pressure inside the chamber by driving the vacuum pump 80when the vacuum break B is conducted. At that time, the controller 50can control the temperature T_(D) of the object 1 by adjusting thedriving and stopping (maneuvering) of the vacuum pump 80 in accordancewith the temperature T_(D) of the object 1 (see FIG. 4A) detected by theobject temperature sensor 40. When the pressure of the chamber interioris reduced, the heat transfer from the placing table 5 a to the object 1through the atmosphere is blocked or attenuated. Thus, the increase inthe temperature T_(D) of the object 1 is interrupted.

As described above, the controller 50 can adjust the restoration of thepressure of the chamber interior during the vacuum break B (see FIG. 4A)by adjusting the gate valve 70 a (see FIG. 2) and the vacuum pump 80 incombination. The heat transfer (rate of heat transfer (heat transfercoefficient)) from the placing table 5 a to the object 1 through theatmosphere is adjusted so as to increase or decrease accordingly, andthe temperature T_(D) of the object 1 (see FIG. 4A) can be controlled.Thus, the overheating of the object 1 can be prevented. In practice, thededicated vacuum breaking valve described above is preferably used foradjusting the restoration of the pressure of the chamber interior. Thevacuum breaking valve in that case is typically a globe valve or needlevalve.

The temperature difference between the temperature T_(B) of the placingcarriage table 5 a (see FIG. 4A) and the temperature T_(D) of the object1 (see FIG. 4A) can be controlled to be smaller than or equal to thespecified temperature difference T_(O) (see FIG. 4A) through a similaradjustment of the restoration of the pressure inside the chamber. Asdescribed above, the vacuum break B (see FIG. 4A) is performed when thetemperature difference in both temperatures becomes the specifiedtemperature difference T_(O) or smaller. When the temperature differencein both temperatures is bigger than the specified temperature differenceT_(O), the vacuum break B is put on standby until the heat transferproceeds and the temperature difference achieves the specifiedtemperature difference T_(O) or smaller. At that time, the temperaturedifference in both temperatures can be controlled to be smaller than orequal to the specified temperature difference T_(O) through theadjustment of the pressure restoration so that heat transfer isconducted with the maximum heat flow rate (Heat transfer quantity/Time(sec.)) from the placing carriage table 5 a to the object 1 while theoverheating of the object 1 is prevented. The configuration as describedabove can arrange a condition for efficiently eliminating thetemperature difference in both temperatures to perform the vacuum breakB at the earliest possible stage. The object 1 can efficiently be cooledthrough the vacuum break B at the earliest possible stage, and thus thecycle time required for soldering can be shortened.

The soldering apparatus 100 further includes the gas supply apparatus 70b as another vacuum breaker 70. The gas supply apparatus 70 b is a gassupply pump that is connected to the inlet port 13 of the vacuum chamber10 and can supply reducing gas such as formic acid gas, inert gas suchas nitrogen gas and argon gas, or ambient air into the chamber. Thevacuum break B (see FIG. 4A) can be performed through driving andadjustment of flow rate of the gas supply apparatus 70 b to supply ofinert gas such as nitrogen gas or ambient air into the chamber, insteadof opening and closing actuation of the gate valve 70 a (see FIG. 2)described above. Alternatively, the vacuum break B can be performed moreefficiently through driving and adjustment of the gas supply apparatus70 b and the gate valve 70 a in combination.

In this embodiment, the gas supply apparatus 70 b is provided so as tosupply the nitrogen gas into the chamber and adjust the pressure (degreeof vacuum) of the chamber interior after the gate valve 70 a (see FIG.2) closes the chamber interior in accordance with the control by thevacuum adjusting part 55 c-2 (see FIG. 3B) provided in the objecttemperature control part 55 c of the control part 55 included in thecontroller 50. The structure as described above can freely adjust thepressure of the chamber interior by combining the adjustment of thesupply of nitrogen gas with the gas supply apparatus 70 b with thedischarge of air inside the chamber through the vacuum pump 80. In thiscase, the pressure of the chamber interior can be adjusted freelywithout relying on the gate valve 70 a, while the vacuum chamber 10 issealed. As described above, the restoration of the pressure by thevacuum break B (see FIG. 4A) can be adjusted freely through the vacuumbreaker 70 and the vacuum pump 80 in combination. In addition, thetemperature of the object or the temperature difference between theobject and the buffer part can preferably be controlled through theadjustment of the degree of vacuum of the chamber interior.

Referring to FIG. 2, the soldering apparatus 100 according to thisembodiment is further described. FIG. 2 is a partial cross-sectionalview in which a part of the vacuum chamber 10 of the soldering apparatus100 is cut away and viewed from a side. FIG. 2 is a view intended toshow the arrangement of the gate valve 70 a included in the solderingapparatus 100 with respect to the vacuum chamber 10, and othercomponents are omitted from the drawing to facilitate understanding. Thegate valves 70 a are disposed on a pair of the walls of the vacuumchamber 10 so as to traverse the conveyor line of the object 1 to besoldered. The conveyor line for conveying the object 1 is constructedwith a plurality of external conveying rollers 16 that forms theconveyor line outside the vacuum chamber 10 and a plurality of conveyingrollers 11 (see FIG. 1A) that form the conveyor line of the chamberinterior described above. The gate valve 70 a opens when the object 1 tobe soldered is transferred into the chamber interior through theconveyor line or the soldered object 1 is transferred out of the chamberinterior. At that time, the gate valve 70 a slides to open from theclosed position of the gate valve 70 a to the vertically upper side ofthe soldering apparatus 100. The gate valve 70 a can seal the chamberinterior as described above when the gate valve 70 a is in the closedposition.

Referring to FIG. 4A, 4B, the control of the heat treatment by thesoldering apparatus 100 according to this embodiment is furtherdescribed. FIG. 4A, 4B are charts showing an example of the control ofthe heat treatment by the soldering apparatus 100. FIG. 4A shows anexample of the temperature control in the case where the buffer part isheated to the first heating target temperature T_(T1) slightly lowerthan the melting temperature of the solder and then the heat transferwaiting time is set for the temperature equalization, and FIG. 4B showsan example of the temperature control in the case where the heattransfer waiting time is not set. The horizontal axis shows time course(in seconds), the left vertical axis shows centigrade temperatures, andthe right vertical axis shows the pressure of the chamber interior (Pa).The temperature T_(D) of the object 1 (see FIG. 1A) detected by theobject temperature sensor 40 (see FIG. 1A) is shown with a thick solidline, and the temperature T_(B) of the placing carriage table 5 a (seeFIG. 1A) detected by the buffer temperature sensor 60 (see FIG. 1A) isshown with a thick dashed line. The pressure of the chamber interiordetected by the pressure gage 81 (see FIG. 1A) is shown with a thinsolid line. The specified control target temperature T_(T2) forsoldering the exemplary object 1 is 325 degrees Celsius, and the meltingtemperature (melting point) T_(m) of the solder in this embodiment is300 degrees Celsius.

With reference to FIG. 4A, an example of the temperature control of thesoldering apparatus 100 is described along the time course. In theexample shown, the heating of the placing carriage table 5 a (seeFIG. 1) by thermal radiation heater 20 a (see FIG. 1A) starts from alapse of approx. 30 seconds. As described above, a slight timedifference arises between the increase of the temperature T_(B) of theplacing carriage table 5 a and the increase of the temperature T_(D) ofthe object 1 (see FIG. 1A). However, the object 1 is energized andheated to the first control target temperature T_(T1) (approx. 280degrees Celsius) slightly lower than 300 degrees Celsius that is themelting temperature (melting point) T_(m) of the solder according tothis embodiment with a high temperature rise rate (Temperature (DegreeC)/Time (sec.)) for approx. 40 seconds until a lapse of approx. 70seconds when the heating is completed. In this embodiment, the heattransfer waiting time is set, as described above, for the temperatureequalization in which the heating by thermal radiation heater 20 a istransferred and conducted to the entire part, from a lapse of approx. 70seconds to approx. 100 seconds after the first control targettemperature T_(T1) is achieved.

After the first control target temperature T_(T1) is achieved, asdescribed above, the adjustment of the heat discharge (cooling) of theplacing carriage table 5 a (see FIG. 1A) by the cooling block 30 a (seeFIG. 1A, 1B) starts, and the pressure of the chamber interior is reducedto the medium vacuum of approx. 100 Pa. A vacuum produced in the chamberinterior causes the heat transfer between the placing carriage table 5 aand the object 1 (see FIG. 1A) to be blocked, and thus the temperaturedifference arises in both temperatures. The temperature of the object 1hardly increases due to the blockage or deterioration of the heattransfer. In order to shorten the cycle time, it is desirable that theobject 1 is heated further through the placing carriage table 5 a. Thus,this embodiment continues the heating by energizing thermal radiationheater 20 a (see FIG. 1A) again. The electrical heating is appropriatelyadjusted to turn on/off in response to a temperature control request forthe object 1. In this case, the cycle time can be shortened further incomparison with the case where heat is applied only by the residual heatof thermal radiation heater 20 a finishing the electrical heating. Thus,the temperature T_(B) of the placing carriage table 5 a diverges fromthe temperature T_(D) of the object 1 and sharply increases. In thesoldering apparatus 100, the heating temperature T_(B) of the placingcarriage table 5 a is not limited to the heating target temperatureT_(T2) of the object 1 or lower by the control, unlike the conventionalapparatus. The temperature T_(B) of the placing carriage table 5 aincreases to exceed the target temperature T_(T2) of the object 1;however, the controller 50 (see FIG. 1A) continues to perform efficientand appropriate controls in accordance with the temperature T_(D) of theobject 1 detected by the object temperature sensor 40 (see FIG. 1A).Thus, the controller 50 does not allow the temperature T_(D) of theobject 1 to overshoot and can set it to the specified control targettemperature T_(T2) of 325 degrees Celsius in a shorter time and withhigher efficiency and accuracy than the conventional apparatus.

The controller 50 (see FIG. 1A) calculates the temperature differencebetween the temperature T_(D) of the object 1 and the temperature T_(B)of the placing carriage table 5 a (see FIG. 1A) respectively detected bythe object temperature sensor 40 and the buffer temperature sensor 60(see FIG. 1A) after the temperature T_(D) of the object 1 (see FIG. 1A)reaches the specified target temperature T_(T2). When the calculatedtemperature difference is smaller than or equal to the specifiedtemperature difference T_(O) that is determined so as not to thermallydamage the object 1 through the vacuum break B, the controller 50operates the gate valve 70 a (see FIG. 2) to perform the vacuum break B.When the temperature difference is bigger than the specified temperaturedifference T_(O), the controller operates the vacuum breaker 70 (gatevalve 70 a (see FIG. 2) and/or the gas supply apparatus 70 b (see FIG.1A) and thus quickly adjusts and eliminates the temperature differencebetween the temperature T_(B) of the placing carriage table 5 a and thetemperature T_(D) of the object 1. The controller operates the vacuumbreaker 70 to restore the pressure of the chamber interior toatmospheric pressure after the temperature difference between thetemperature T_(B) of the placing carriage table 5 a and the temperatureT_(D) of the object 1 becomes smaller than or equal to the specifiedtemperature difference T_(O) and while the temperature T_(D) of theobject 1 is higher than or equal to the melting temperature (meltingpoint) T_(m) of the solder.

The increase in the temperature T_(D) of the object 1 (see FIG. 1A)associated with the vacuum break B is controlled to be a slighttemperature increase as shown in the drawing. Natural cooling throughambient air is recovered after the vacuum break B, and thus thetemperature T_(D) of the object 1 and the temperature T_(B) of theplacing carriage table 5 a (see FIG. 1A) sharply decrease. At this time,the decrease in the temperature T_(B) of the placing carriage table 5 acooled in combination with the cooling block 30 a (see FIG. 1A, 1B)precedes the decrease in the temperature T_(D) of the object 1 by asmall time difference.

Good soldering can be achieved through the control of the solderingapparatus 100 as described above, in which the object 1 (see FIG. 1A) isnot subjected to thermal destruction but can securely be heated to thespecified heating target temperature T_(T2) and soldered, and the cycletime for soldering can be shortened as well. The soldering with thesoldering apparatus 100 according to this embodiment can shorten thecycle time by approx. 40 seconds as compared with the soldering with theconventional soldering apparatus (see Claim 1 of Patent Document 1, forexample).

The soldering apparatus 100 according to this embodiment is described assimultaneously heat-treating and soldering the plural (six) objects 1;however, other embodiments may heat-treat and solder only one object 1to be soldered by the soldering apparatus 100. In this case,heat-treatment (temperature control) exclusively suitable for solderingonly one object 1 to be soldered can be performed without consideringthe state of heat-treatment of other objects 1.

This embodiment is described such that the temperature T_(D) of the mostheat-sensitive object 1 among the plural (six) objects 1 is detectedwith one object temperature sensor 40 and the soldering is performed.However, other embodiments may detect all of the temperature T_(D) ofthe plural objects 1 to be heat-treated with a plurality of objecttemperature sensors 40 and apply all of the detected temperature T_(D)of the objects 1 to the temperature control of the soldering apparatus100. In this case, further precise temperature control of all objects 1can be performed.

This embodiment is described such that the object temperature sensor 40and the buffer temperature sensor 60 are provided as the radiationthermometers that can detect the temperature without blockage of thevacuum. However, other embodiments may be provided with contactthermometers as the temperature sensors which come into contact with theobject 1 and the placing carriage table 5 a and detect the temperatures,respectively. A thermocouple can be used as the contact thermometer, forexample. In this case, thermocouple can be provided to be embedded inthe placing carriage table 5 a so as to detect the temperature T_(B) ofthe placing carriage table 5 a. Thermocouple in the above case is notblocked by the reflections of heat radiation inside the chamber and candetect the temperatures more readily. In addition, thermocouple has asimpler mechanical structure and thus can be provided in the solderingapparatus 100 more easily.

This embodiment is described such that the object temperature sensor 40detects the temperature T_(D) of the electronic component 2 forming theobject 1. However, other embodiments may be provided with the objecttemperature sensor 40 for detecting the temperature T_(D) of thesubstrate 3 forming the object 1. Also in this case, the change in theheat transfer (rate of heat transfer (heat transfer coefficient))between the substrate 3 forming the object 1 to be soldered and theplacing carriage table 5 a can be incorporated into the control, and thetemperature for soldering can be controlled appropriately even in avacuum.

Thermal radiation heater 20 a according to this embodiment is describedas a halogen heater. However, other embodiments may be provided with acarbon heater that encloses a carbon fiber filament in inert gas asthermal radiation heater 20 a. In this case, the heater can radiate muchmore infrared rays with a wavelength range between approx. 2 μm andapprox. 4 μm close to the wavelength of absorption spectrum peak ofwater (approx. 3 μm wavelength). Thus, when the object 1 has a watercontent (the electronic component such as a semiconductor package andthe substrate typically have some hygroscopic properties), the carbonheater as the thermal radiation heater 20 a can preferably apply heat tothe object 1 through water contained in the object 1 and thus canefficiently apply heat to the object 1. Further other embodiments may beprovided with a nichrome wire heater that encloses a nichrome filamentin air as thermal radiation heater 20 a. In this case, thermal radiationheater 20 a con be provided more easily.

Thermal radiation heater 20 a according to this embodiment is describedas being provided in rod shape. However, thermal radiation heater 20 ain another embodiment may be provided in any shape such as arc shape andsphere shape corresponding to the shape and the arrangement of thesolder joint part 4 of the object 1.

This embodiment is described such that the soldering apparatus 100reduces the pressure of the chamber interior to a vacuum when thetemperature T_(D) of the object 1 is heated to the specified firstcontrol target temperature T_(T1) lower than the melting temperature(melting point) T_(m) of the solder. However, other embodiment may beconfigured to reduce the pressure of the chamber interior to produce avacuum after the temperature T_(D) of the object 1 is heated to themelting temperature (melting point) T_(m) of the solder or higher withinthe range where the formation of the oxide film on the surface of thesolder joining the conducting point of the object 1 is not harmful so asto substantially affect the quality of soldering (such as mechanicalbonding strength and electrical conductivity). In this case, the timefor heating the object 1 in ambient air can be increased further, andthus the object 1 can be heated more efficiently.

The temperature control of the soldering apparatus 100 in thisembodiment is described such that the specified heat transfer waitingtime is set for equalizing the temperature of entire parts of theplacing carriage table 5 a and the object 1 after the heating to thefirst heating target temperature T_(T1) by thermal radiation heater 20 ais completed. However, the soldering apparatus 100 may be operated undertemperature control without setting the heat transfer waiting time asshown in FIG. 4B. In this case, heating can be performed with the secondheating target temperature T_(T2) determined as a control targettemperature from the start of heating, and the heat transfer waitingtime can be saved. Thus, the cycle time for soldering can be shortenedfurthermore.

This embodiment is described such that the pressure of the chamberinterior is reduced to a vacuum after the heating to the first heatingtarget temperature T_(T1) by thermal radiation heater 20 a is completed.However, other embodiments may perform soldering by reducing thepressure of the chamber interior before the start of heating or at thesame time of the start of heating by thermal radiation heater 20 a. Inthis case, the pressure-reducing operation and the heating operation canbe performed concurrently, and thus the cycle time for soldering can beshortened.

The embodiment shown in FIG. 4B is configured to reduce the pressure ofthe chamber interior before the start of heating by thermal radiationheater. Heating is performed in a vacuum from the start of heating, andthus there is a divergence in temperature between the temperature T_(B)of the placing carriage table and the temperature T_(D) of the objectfrom the start of heating. However, the heat transfer waiting time isnot set and the pressure-reducing operation is not necessarily put onstandby as described above, and thus the cycle time for soldering isshortened further. This embodiment is configured to perform the vacuumbreak B when the temperature T_(B) of the placing carriage table agreeswith the temperature T_(D) of the object. The vacuum break B in thiscase is said to be performed within the range of the specifiedtemperature difference T_(O). In this case, the rise of the temperatureT_(D) of the object after the vacuum break B is reduced further, and therise of the temperature T_(D) of the object is substantially prevented.In other words, this configuration can perform the vacuum break Bwithout rising in the temperature T_(D) of the object.

The soldering apparatus 100 according to this embodiment is described asincluding one vacuum chamber 10 and being provided with thermalradiation heater 20 a and the cooler 30 in the same vacuum chamber 10.However, the soldering apparatus in other embodiments may include aplurality of vacuum chambers and be provided with thermal radiationheater 20 a and the cooler 30 in different vacuum chambers. In thiscase, the heating by thermal radiation heater 20 a and the heatdischarge (cooling) by the cooler 30 can be prevented from interferingwith each other, and thus efficient heating and heat discharge (cooling)can be conducted.

The cooling block 30 a according to this embodiment is described asbeing formed in comb shape. However, the cooling block 30 a in anotherembodiment may be formed in various shapes that are formed inappropriate shape corresponding to the shape of thermal radiation heater20 a within a range where the cooling block is disposed adjacently tothermal radiation heater 20 a and thus can efficiently cool the placingcarriage table 5 a.

This embodiment is described as soldering under a condition where theobject 1 is placed on the placing carriage table 5 a. However, otherembodiments may further include a pushing member for pushing the object1 placed on the placing carriage table 5 a against the placing carriagetable 5 a by appropriate force. In this case, the object 1 is pushedagainst the placing carriage table 5 a, and thus the contact state (andheat transfer) of both components can be in good condition further.Thus, the efficiency of soldering by the soldering apparatus is furtherimproved, and the cycle time can be shortened.

The cooling block 30 a according to this embodiment is described asbeing driven by the drive unit 30 b so as to approach and move away fromthe placing carriage table 5 a and cool. However, other embodiments maybe configured such that the placing carriage table 5 a where the object1 is placed is driven to approach and move away from the cooling block30 a provided fixedly and cool. The placing carriage table 5 a and thecooling block 30 a may be provided to relatively approach and move awayfrom each other.

This embodiment is described such that the comb tooth part of thecooling block 30 a moves, when cooling the object 1, the placingcarriage table 5 a away from the thermal radiation heater 20 a with aspecified spacing and also reduces the heating efficiency of the placingcarriage table 5 a by thermal radiation heater 20 a through the blockageof diffusion of heat radiation, resulting in the improvement of thecooling efficiency of the placing carriage table 5 a and the object 1.However, other embodiments may be configured to control the temperatureof the object 1 by adjusting drive amount of the cooling block 30 a tochange heat discharge efficiency (cooling efficiency) from the placingcarriage table 5 a. In this case, the temperature of the object 1 can becontrolled through the change of the heat discharge efficiency (coolingefficiency) from the placing carriage table 5 a as a buffer part.

This embodiment is described such that the heat capacity of the placingcarriage table 5 a provided as the buffer part is typically defined tobe larger than that of the object 1. However, it may be sufficient ifthe buffer part can be interposed between the object 1 (specifically,electronic component 2) and thermal radiation heater 20 a (or coolingblock 30 a) to thermally buffer the heating (or cooling) by thermalradiation heater 20 a (or cooling block 30 a). Thus, in otherembodiments, the heat capacity of the placing carriage table 5 a may besmaller than or equal to that of the object 1 within the range where theplacing carriage table thermally buffers the heating (or cooling) bythermal radiation heater 20 a (or cooling block 30 a).

This embodiment is described such that heating by thermal radiationheater 20 a is conducted through the heat radiation with the specifiedheat radiation output and the temperature of the object 1 is controlledthrough on/off adjustment. However, other embodiments may be configuredsuch that heating by thermal radiation heater 20 a is conducted throughthe adjustment of both the heat radiation output andenergization/de-energization in combination and the PID control isperformed in accordance with the temperature T_(D) of the object 1 as isthe case with the cooler 30. In this case, the temperature of the object1 can adequately be controlled through heating adjustment by thermalradiation heater 20 and heat discharge adjustment (cooling adjustment)by the cooler 30 in combination.

This embodiment is described as performing the temperature control ofthe object 1 through the adjustment of heat discharge (cooling) by thecooling block 30 a on the basis of theproportional-plus-integral-plus-derivative control (PID control).However, other embodiments may perform the temperature control bycooling on the basis of any of proportional control,proportional-plus-derivative control, or proportional-plus-integralcontrol. In this case, the soldering apparatus 100 can be provided moreeasily.

This embodiment is described such that the soldering apparatus 100includes the gas supply apparatus 70 b as the vacuum breaker 70 inaddition to the gate valve 70 a. However, other embodiments may includeonly the gate valve 70 a as the vacuum breaker 70 without the gas supplyapparatus 70 b. In this case, since the vacuum break B can be performedwith the gate valve 70 a, the soldering apparatus 100 can be providedmore easily.

This embodiment describes the soldering apparatus 100 for soldering theobject 1 in order to exemplify the heat-bonding apparatus according tothe invention of the present application. However, heat-bondingperformed by the heat-bonding apparatus according to the invention ofthe present application is not limited to soldering. The heat-bondingapparatus according to the present invention can perform a wide varietyof heat-bonding for bonding the object (workpiece) by heating andcooling the bonding material. Thus, the heat-bonding apparatus such asthe soldering apparatus 100 according to this embodiment may beconfigured to perform brazing with the metal bonding materials andbonding and welding with resin bonding materials or glass bondingmaterials.

Examples of brazing with the metal bonding materials include so calledthe soldering with soft solder that is an alloy of lead, tin, antimony,cadmium, or zinc, for example, and brazing with hard solder that is analloy of silver, brass, aluminum alloy, phosphorus copper, nickel, orgold, for example. Examples of heat-bonding with the resin bondingmaterials include the heat-bonding with thermoplastic resins havingconductivity or insulation properties. The resin bonding material may bethe one which solidifies by being heated to the specified temperature asis the case with thermosetting resin. In addition, the glass bondingmaterials such as low-melting glass formulated withelectrically-conducting materials may be used. Any of the heat-bondingmay be required to be performed in a vacuum in order to avoid theformation of the oxide film that blocks the bonding.

Referring to FIG. 5, a soldering apparatus as the heat-bonding apparatusaccording to a second embodiment of the present invention is described.The soldering apparatus according to this embodiment differs from thesoldering apparatus 100 according to the first embodiment only in a partof structure of the placing carriage table 5 c where the object 1 isplaced and the cooling block 30 a. Thus, FIG. 5 illustrating thesoldering apparatus according to this embodiment only shows an enlargedview of the different part from the soldering apparatus 100 describedabove with other parts omitted for easily understanding. FIG. 5A is aview showing a heating state of the soldering apparatus andcorresponding to FIG. 1A. FIG. 5B is a view showing a heat dischargingstate (cooling state) and corresponding to FIG. 1B.

The placing carriage table 5 c included in the soldering apparatusaccording to this embodiment is described. The different point of theplacing carriage table 5 c from the placing carriage table 5 a (seeFIG. 1) of the soldering apparatus 100 described above is that theopening windows (holes) 6 are formed in the placing carriage table 5 c.Thus, the soldering apparatus according to this embodiment is configuredsuch that thermal radiation heater 20 a applies heat to the substrate 3through the opening windows 6. A part of the cooling plate of thecooling block 30 a is provided so as to make contact with the substrate3 to discharge heat of the substrate 3. The buffer temperature sensor 60(see FIG. 1A) is provided so as to detect the temperature T_(B) of thesubstrate 3 (see FIG. 4A) as the buffer part.

In this embodiment, the substrate 3 (and the solder joint part 4)functions as the buffer part for the electronic component 2. Thesubstrate 3 (and the solder joint part 4) interposes between theheat-sensitive and thermally deformable electronic component 2 andthermal radiation heater 20 a and prevents the overheating of theelectronic component 2. The cooling block 30 a approaches and moves awayfrom the substrate 3 and adjusts the heat discharge (cooling) from thesubstrate 3. The substrate 3 prevents thermal deformation of theelectronic component 2 and achieves efficient soldering by thermallyequalizing the heating and the cooling with thermal radiation heater 20a and the cooling block 30 a in terms of space and time and transferringheat to the electronic component 2. The heat capacity of the substrate 3is smaller than that of the placing carriage table 5 a (see FIG. 1)described above but large enough in comparison with the electroniccomponent 2.

As described above, the electronic component 2 that is the object 1 tobe soldered in this embodiment is placed on the substrate 3 (and thesolder joint part 4) as the buffer part and located on the downstreamside of heat transfer through the contact face between the substrate 3and the electronic component 2 to be soldered. In this case, the object1 can be prevented from being overheated in a similar manner to thesoldering apparatus 100 described above, and the object 1 can be heatedto the control target temperature T_(T2) (see FIG. 4A) without fail andefficiently soldered in short cycle time.

Referring to FIG. 6, a soldering apparatus 200 as the heat-bondingapparatus according to a third embodiment of the present invention isdescribed. The structure of a heat treatment mechanism in the solderingapparatus 200 differs from the soldering apparatus 100 described aboveonly in the structure of a fixed placing table 5 b (placing table 5)where the object 1 is placed. Thus, only the structure of the fixedplacing table 5 b is described for the soldering apparatus 200. Thedifferent point of the fixed placing table 5 b from the placing carriagetable 5 a (see FIG. 1) of the soldering apparatus 100 described above isthat the fixed placing table 5 b is fixed to the other main componentsin the soldering apparatus 200. The fixed placing table 5 b includes anelectrothermal heater 20 b as the heater 20 and a coolant circulatingcircuit 30 c as the cooler 30 in its inside.

The fixed placing carriage table 5 b is made of copper that has a highthermal conductivity. Thus, the object 1 heat-treated can efficiently beheated or cooled through the fixed placing carriage table 5 b. Theelectrothermal heater 20 b is provided as a sheathed heater. In thisembodiment, the fixed placing table 5 b interposing between the object 1and the electrothermal heater 20 b and the coolant circulating circuit30 c functions as the buffer part. The fixed placing carriage table 5 bis not moved (driven) unlike the case with the placing carriage table 5a and the cooling block 30 a (see FIG. 1) of the soldering apparatus 100described above. Thus, the fixed placing table 5 b is not provided withdriving mechanisms such as the drive unit (air cylinder) 30 b and theguide post 15 (see FIG. 1A) that are included in the aforementionedsoldering apparatus 100 described above. Thus, the soldering apparatus200 can be provided more easily than the aforementioned solderingapparatus 100.

The coolant circulating circuit 30 c according to this embodiment canremove, through direct heat-discharging (cooling), the residual heatreleased by the electrothermal heater 20 b after finishing theelectrical heating. Thus, the soldering apparatus 200 can control thetemperature of the object 1 more efficiently than the aforementionedsoldering apparatus 100. The adjustment of heat discharge (cooling) fromthe fixed placing table 5 b with the coolant circulating circuit 30 ccan be performed by adjusting, with the coolant supplying unit 90, theflow rate of the coolant circulating in the coolant circulating circuit30 c. Specifically, the controller 50 can control the temperature T_(D)of the object 1 by adjusting the flow rate of the cooling watercirculating in the coolant circulating circuit 30 c in accordance withthe temperature T_(D) of the object 1 (see FIG. 4A) detected by theobject temperature sensor 40. The adjustment of heat discharge (cooling)can also be performed in the aforementioned soldering apparatus 100. Inthe case of using the soldering apparatus 200 according to thisembodiment, the object 1 can be prevented from being overheated in asimilar manner to the soldering apparatus 100 described above, and theobject 1 can be heated to the target temperature T_(T2) (see FIG. 4A)without fail and efficiently soldered in short cycle time.

Referring to a flowchart in FIG. 7, a method of manufacturing a solderedproduct as a heat-bonded product according to a fourth embodiment of thepresent invention is described. In the method of manufacturing thesoldered product according to this embodiment, the object 1 to besoldered (see FIG. 1 and FIG. 6) and the buffer part 5 (see FIG. 1A andFIG. 6) are placed into contact with each other and loaded into thesoldering apparatus (see FIG. 1A and FIG. 6) (Step M1). The solderingapparatus is used to solder the object 1 (Step M2).

In the Step M1 of loading, the object 1 to be soldered (see FIG. 1A andFIG. 6) and the buffer part 5 (see FIG. 1 and FIG. 6) are placed intocontact with each other and positioned under vacuum inside the chamber(Step M1 a).

In the Step M2 of soldering, the buffer part 5 (see FIG. 1A and FIG. 6)is heated to the specified first control target temperature T_(T1) (seeFIG. 4A) (Step M2 a). Then, the heat of the heated buffer part 5 isdischarged (Step M2 b). The temperature T_(D) (see FIG. 4A) of theobject heated through the buffer part 5 is then detected (Step M2 c),and the heat discharge from the buffer part 5 is adjusted so that thetemperature T_(D) of the object reaches the specified second controltarget temperature T_(T2) (see FIG. 4A) (Step M2 d).

Then, the temperature T_(D) (see FIG. 4A) of the object and thetemperature T_(B) (see FIG. 4A) of the buffer part 5 (see FIG. 1A andFIG. 6) are detected (Step M2 e), and the vacuum break B (see FIG. 4A)is performed when the temperature difference between the temperatureT_(D) of the object and the temperature T_(B) of the buffer part 5 fallswithin the range of the specified temperature differences T_(O) (seeFIG. 4A) (Step M2 f). The method of manufacturing the soldered productmay further include any of the control steps described in the aboveembodiments in addition to the steps described above. For example, thetemperature difference between the buffer part and the object iscontrolled by the adjustment of the pressure in a vacuum so that thetemperature difference may be smaller than T_(O).

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention (especially in the context of thefollowing claims) is to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. The terms “comprising”, “having”, “including” and “containing”are to be construed as open-ended terms (i.e., meaning “including, butnot limited to,”) unless otherwise noted. Recitation of ranges of valuesherein are merely intended to serve as a shorthand method of referringindividually to each separate value falling within the range, unlessotherwise indicated herein, and each separate value is incorporated intothe specification as if it were individually recited herein. All methodsdescribed herein can be performed in any suitable order unless otherwiseindicated herein or otherwise clearly contradicted by context. The useof any and all examples, or exemplary language (e.g., “such as”)provided herein, is intended merely to better illuminate the inventionand does not pose a limitation on the scope of the invention unlessotherwise claimed. No language in the specification should be construedas indicating any non-claimed element as essential to the practice ofthe invention.

Preferred embodiments of this invention are described herein, includingthe best mode known to the inventors for carrying out the invention.Variations of those preferred embodiments may become apparent to thoseof ordinary skill in the art upon reading the foregoing description. Theinventors expect skilled artisans to employ such variations asappropriate, and the inventors intend for the invention to be practicedotherwise than as specifically described herein. Accordingly, thisinvention includes all modifications and equivalents of the subjectmatter recited in the claims appended hereto as permitted by applicablelaw. Moreover, any combination of the above-described elements in allpossible variations thereof is encompassed by the invention unlessotherwise indicated herein or otherwise clearly contradicted by context.

DESCRIPTION OF REFERENCE NUMERALS AND SYMBOLS

-   1: object (workpiece)-   2: electronic component-   3: substrate-   4: solder joint part-   5: placing table (buffer part)-   5 a: placing carriage table-   5 b: fixed placing table-   5 c: placing carriage table with opening windows-   6: opening window-   10: vacuum chamber-   11: conveying roller-   12: view window-   13: inlet port-   14: exhaust port-   15: guide post-   16: external conveying roller-   20: heater-   20 a: thermal radiation heater-   20 b: electrothermal heater-   30: cooler-   30 a: cooling block-   30 b: drive unit (air cylinder)-   30 c: coolant circulating circuit-   31: positioning pin-   40: object temperature sensor (radiation thermometer)-   50: controller-   51: central processing unit-   52: heater operating part-   53: cooler operating part-   54: object temperature sensor operating part-   55: control part-   55 a: set value memory unit-   55 b: pressure-reducing operation part-   55 c: object temperature control part-   55 d: vacuum breaking operation part-   56: buffer temperature sensor operating part-   57: vacuum breaker operating part-   58: vacuum pump operating part-   59: coolant supplying unit operating part-   60: buffer temperature sensor (radiation thermometer)-   70: vacuum breaker-   70 a: gate valve-   70 b: gas supply apparatus-   80: vacuum pump (air displacement pump)-   81: pressure gage-   90: coolant supplying unit-   100: soldering apparatus (heat-bonding apparatus)-   200: soldering apparatus (heat-bonding apparatus)

1. A heat-bonding apparatus comprising: a vacuum chamber for housing anobject to be heat-bonded and a buffer part; a heater for applying heatto the buffer part placed into contact with the object housed in thevacuum chamber; a cooler for discharging heat of the buffer part heatedby the heater; an object temperature sensor for detecting a temperatureof the object heated through the buffer part; and a controller forcontrolling the temperature of the object to be a specified targettemperature suitable for heat-bonding by adjusting heat discharge fromthe buffer part with the cooler in accordance with the detectedtemperature of the object.
 2. The heat-bonding apparatus according toclaim 1, wherein the heater is provided as a thermal radiation heaterfor heating the buffer part through thermal radiation; the coolerincludes a cooling block and a drive unit for relatively driving thecooling block to approach and move away from the buffer; and thecontroller is configured to control the temperature of the object byadjusting approach and separation of the cooling block.
 3. Theheat-bonding apparatus according to claim 1, wherein the buffer part isprovided as a placing table for placing the object, and the heater andthe cooler are provided inside the placing table.
 4. The heat-bondingapparatus according to claim 1, further comprising: a buffer temperaturesensor for detecting a temperature of the buffer part; and a vacuumbreaker for breaking a vacuum in the vacuum chamber, wherein thecontroller is configured to break the vacuum in the vacuum chamber byoperating the vacuum breaker when a temperature difference between afirst detected temperature of the object temperature sensor and a seconddetected temperature of the buffer temperature sensor falls within arange of specified temperature differences.
 5. The heat-bondingapparatus according to claim 4, wherein the controller is configured tolower the temperature of the object below a melting point of a bondingmaterial after breaking the vacuum in the vacuum chamber.
 6. Theheat-bonding apparatus according to claim 4, further comprising: avacuum pump for discharging air inside the vacuum chamber, wherein thecontroller is configured to control the temperature of the object to bethe specified target temperature by adjusting heat transfer from thebuffer part to the object through adjusting air discharge with thevacuum pump and vacuum break with the vacuum breaker in combination. 7.A method of manufacturing a heat-bonded product, comprising the stepsof: providing the heat-bonding apparatus according to claim 1, placingto load the object to be heat-bonded in contact with the buffer partinto the heat-bonding apparatus; and heat-bonding the object using theheat-bonding apparatus.
 8. A method of manufacturing a heat-bondedproduct, comprising the steps of: placing an object to be heat-bondedand a buffer part under vacuum, the object being arranged into contactwith the buffer part; heating the buffer part under vacuum; dischargingheat of the heated buffer part; detecting a temperature of the objectheated through the buffer part; and controlling the temperature of theobject to be a specified target temperature suitable for heat-bonding byadjusting heat discharge in the step of heat discharging in accordancewith the detected temperature of the object.